Refactor var to let/const or this

2025-01-11 07:18:08 +00:00 · 2019-05-30 09:05:16 +03:00 · 2019-05-30 09:05:16 +03:00 · fe0fb3a251
commit fe0fb3a251
parent b530e19a44
32 changed files with 880 additions and 882 deletions
--- a/src/webui/www/private/addtrackers.html
+++ b/src/webui/www/private/addtrackers.html
@ -32,7 +32,7 @@
            $('trackersUrls').focus();
            $('addTrackersButton').addEvent('click', function(e) {
                new Event(e).stop();
-                var hash = new URI().getData('hash');
+                const hash = new URI().getData('hash');
                new Request({
                    url: 'api/v2/torrents/addTrackers',
                    method: 'post',
--- a/src/webui/www/private/confirmdeletion.html
+++ b/src/webui/www/private/confirmdeletion.html
@ -10,8 +10,8 @@
    <script>
        'use strict';
        var hashes = new URI().getData('hashes').split('|');
        window.addEvent('domready', function() {
            const hashes = new URI().getData('hashes').split('|');
            $('cancelBtn').focus();
            $('cancelBtn').addEvent('click', function(e) {
                new Event(e).stop();
@ -20,8 +20,8 @@
            $('confirmBtn').addEvent('click', function(e) {
                parent.torrentsTable.deselectAll();
                new Event(e).stop();
-                var cmd = 'api/v2/torrents/delete';
+                const cmd = 'api/v2/torrents/delete';
-                var deleteFiles = $('deleteFromDiskCB').get('checked');
+                const deleteFiles = $('deleteFromDiskCB').get('checked');
                new Request({
                    url: cmd,
                    method: 'post',
--- a/src/webui/www/private/download.html
+++ b/src/webui/www/private/download.html
@ -140,9 +140,9 @@
    <script>
        'use strict';
-        var encodedUrls = new URI().getData('urls');
+        const encodedUrls = new URI().getData('urls');
        if (encodedUrls) {
-            var urls = [];
+            const urls = [];
            encodedUrls.split('|').each(function(url) {
                urls.push(decodeURIComponent(url));
            });
@ -151,7 +151,7 @@
                $('urls').set('value', urls.join("\n"));
        }
-        var submitted = false;
+        let submitted = false;
        $('downloadForm').addEventListener("submit", function() {
            $('startTorrentHidden').value = $('startTorrent').checked ? 'false' : 'true';
--- a/src/webui/www/private/downloadlimit.html
+++ b/src/webui/www/private/downloadlimit.html
@ -24,9 +24,9 @@
        <script>
            'use strict';
-            var hashes = new URI().getData('hashes').split('|');
+            const hashes = new URI().getData('hashes').split('|');
-            var setDlLimit = function() {
+            const setDlLimit = function() {
-                var limit = $("dllimitUpdatevalue").value.toInt() * 1024;
+                const limit = $("dllimitUpdatevalue").value.toInt() * 1024;
                if (hashes[0] == "global") {
                    new Request({
                        url: 'api/v2/transfer/setDownloadLimit',
--- a/src/webui/www/private/edittracker.html
+++ b/src/webui/www/private/edittracker.html
@ -29,17 +29,17 @@
                }
            }).activate();
-            var currentUrl = new URI().getData('url');
+            const currentUrl = new URI().getData('url');
            if (!currentUrl)
                return false;
-            var decodedUrl = decodeURIComponent(currentUrl);
+            const decodedUrl = decodeURIComponent(currentUrl);
            $('trackerUrl').value = decodedUrl;
            $('trackerUrl').focus();
            $('editTrackerButton').addEvent('click', function(e) {
                new Event(e).stop();
-                var hash = new URI().getData('hash');
+                const hash = new URI().getData('hash');
                new Request({
                    url: 'api/v2/torrents/editTracker',
                    method: 'post',
--- a/src/webui/www/private/filters.html
+++ b/src/webui/www/private/filters.html
@ -32,7 +32,7 @@
 <script>
    'use strict';
-    var categoriesFilterContextMenu = new CategoriesFilterContextMenu({
+    const categoriesFilterContextMenu = new CategoriesFilterContextMenu({
        targets: '.categoriesFilterContextMenuTarget',
        menu: 'categoriesFilterMenu',
        actions: {
--- a/src/webui/www/private/installsearchplugin.html
+++ b/src/webui/www/private/installsearchplugin.html
@ -29,7 +29,7 @@
 <script>
    'use strict';
-    var initInstallSearchPlugin = function() {
+    this.initInstallSearchPlugin = function() {
        new Keyboard({
            defaultEventType: 'keydown',
            events: {
@ -37,7 +37,7 @@
                    // accept enter key as a click
                    new Event(e).stop();
-                    var elem = e.event.srcElement;
+                    const elem = e.event.srcElement;
                    if ((elem.id === "newPluginPath") || (elem.id === "newPluginOk"))
                        newPluginOk();
                    else if (elem.id === "newPluginCancel")
@ -49,8 +49,8 @@
        $('newPluginPath').select();
    };
-    var newPluginOk = function() {
+    this.newPluginOk = function() {
-        var path = $("newPluginPath").get("value").trim();
+        const path = $("newPluginPath").get("value").trim();
        if (path)
            new Request({
                url: 'api/v2/search/installPlugin',
--- a/src/webui/www/private/newcategory.html
+++ b/src/webui/www/private/newcategory.html
@ -30,10 +30,10 @@
        }).activate();
        window.addEvent('domready', function() {
-            var uriAction = safeTrim(new URI().getData('action'));
+            const uriAction = safeTrim(new URI().getData('action'));
-            var uriHashes = safeTrim(new URI().getData('hashes'));
+            const uriHashes = safeTrim(new URI().getData('hashes'));
-            var uriCategoryName = safeTrim(new URI().getData('categoryName'));
+            const uriCategoryName = safeTrim(new URI().getData('categoryName'));
-            var uriSavePath = safeTrim(new URI().getData('savePath'));
+            const uriSavePath = safeTrim(new URI().getData('savePath'));
            if (uriAction === "edit") {
                if (!uriCategoryName)
@ -51,10 +51,10 @@
            $('categoryNameButton').addEvent('click', function(e) {
                new Event(e).stop();
-                var savePath = $('savePath').value.trim();
+                const savePath = $('savePath').value.trim();
-                var categoryName = $('categoryName').value.trim();
+                const categoryName = $('categoryName').value.trim();
-                var verifyCategoryName = function(name) {
+                const verifyCategoryName = function(name) {
                    if ((name === null) || (name === ""))
                        return false;
                    if (name.match("^([^\\\\\\/]|[^\\\\\\/]([^\\\\\\/]|\\/(?=[^\\/]))*[^\\\\\\/])$") === null) {
--- a/src/webui/www/private/preferences_content.html
+++ b/src/webui/www/private/preferences_content.html
@ -1084,34 +1084,34 @@
    'use strict';
    // Downloads tab
-    var WatchedFoldersTable = new HtmlTable($("watched_folders_tab"));
+    this.WatchedFoldersTable = new HtmlTable($("watched_folders_tab"));
-    var updateTempDirEnabled = function() {
+    this.updateTempDirEnabled = function() {
-        var isTempDirEnabled = $('temppath_checkbox').getProperty('checked');
+        const isTempDirEnabled = $('temppath_checkbox').getProperty('checked');
        $('temppath_text').setProperty('disabled', !isTempDirEnabled);
    };
-    var addWatchFolder = function() {
+    this.addWatchFolder = function() {
-        var new_folder = $('new_watch_folder_txt').getProperty('value').trim();
+        const new_folder = $('new_watch_folder_txt').getProperty('value').trim();
        if (new_folder.length <= 0) return;
-        var new_other = $('new_watch_folder_other_txt').getProperty('value').trim();
+        const new_other = $('new_watch_folder_other_txt').getProperty('value').trim();
        if (new_other.length <= 0) return;
-        var new_select = $('new_watch_folder_select').getProperty('value').trim();
+        const new_select = $('new_watch_folder_select').getProperty('value').trim();
-        var i = $('watched_folders_tab').getChildren('tbody')[0].getChildren('tr').length;
+        const i = $('watched_folders_tab').getChildren('tbody')[0].getChildren('tr').length;
        pushWatchFolder(i, new_folder, new_select, new_other);
        // Clear fields
        $('new_watch_folder_txt').setProperty('value', '');
-        var elt = $('new_watch_folder_select');
+        const elt = $('new_watch_folder_select');
        elt.setProperty('value', 'watch_folder');
-        var text = elt.options[elt.selectedIndex].innerHTML;
+        const text = elt.options[elt.selectedIndex].innerHTML;
        $('new_watch_folder_other_txt').setProperty('value', text);
    };
-    var changeWatchFolderSelect = function(item) {
+    this.changeWatchFolderSelect = function(item) {
        if (item.value == "other") {
            item.nextElementSibling.hidden = false;
            item.nextElementSibling.value = 'QBT_TR(Type folder here)QBT_TR[CONTEXT=HttpServer]';
@ -1119,15 +1119,15 @@
        }
        else {
            item.nextElementSibling.hidden = true;
-            var text = item.options[item.selectedIndex].innerHTML;
+            const text = item.options[item.selectedIndex].innerHTML;
            item.nextElementSibling.value = text;
        }
    };
-    var pushWatchFolder = function(pos, folder, sel, other) {
+    this.pushWatchFolder = function(pos, folder, sel, other) {
-        var myinput = "<input id='text_watch_" + pos + "' type='text' value='" + folder + "'>";
+        const myinput = "<input id='text_watch_" + pos + "' type='text' value='" + folder + "'>";
-        var disableInput = (sel != "other");
+        const disableInput = (sel != "other");
-        var mycb = "<div class='select-watched-folder-editable'>"
+        const mycb = "<div class='select-watched-folder-editable'>"
            + "<select id ='cb_watch_" + pos + "' onchange='changeWatchFolderSelect(this)'>"
            + "<option value='watch_folder'>QBT_TR(Monitored folder)QBT_TR[CONTEXT=ScanFoldersModel]</option>"
            + "<option value='default_folder'>QBT_TR(Default save location)QBT_TR[CONTEXT=ScanFoldersModel]</option>"
@ -1138,20 +1138,20 @@
        WatchedFoldersTable.push([myinput, mycb]);
        $('cb_watch_' + pos).setProperty('value', sel);
        if (disableInput) {
-            var elt = $('cb_watch_' + pos);
+            const elt = $('cb_watch_' + pos);
            other = elt.options[elt.selectedIndex].innerHTML;
        }
        $('cb_watch_txt_' + pos).setProperty('value', other);
    };
-    var getWatchedFolders = function() {
+    this.getWatchedFolders = function() {
-        var nb_folders = $("watched_folders_tab").getChildren("tbody")[0].getChildren("tr").length;
+        const nb_folders = $("watched_folders_tab").getChildren("tbody")[0].getChildren("tr").length;
-        var folders = new Hash();
+        const folders = new Hash();
-        for (var i = 0; i < nb_folders; ++i) {
+        for (let i = 0; i < nb_folders; ++i) {
-            var fpath = $('text_watch_' + i).getProperty('value').trim();
+            const fpath = $('text_watch_' + i).getProperty('value').trim();
            if (fpath.length > 0) {
-                var other;
+                let other;
-                var sel = $('cb_watch_' + i).getProperty('value').trim();
+                const sel = $('cb_watch_' + i).getProperty('value').trim();
                if (sel == "other") {
                    other = $('cb_watch_txt_' + i).getProperty('value').trim();
                }
@ -1164,18 +1164,18 @@
        return folders;
    };
-    var updateExportDirEnabled = function() {
+    this.updateExportDirEnabled = function() {
-        var isExportDirEnabled = $('exportdir_checkbox').getProperty('checked');
+        const isExportDirEnabled = $('exportdir_checkbox').getProperty('checked');
        $('exportdir_text').setProperty('disabled', !isExportDirEnabled);
    };
-    var updateExportDirFinEnabled = function() {
+    this.updateExportDirFinEnabled = function() {
-        var isExportDirFinEnabled = $('exportdirfin_checkbox').getProperty('checked');
+        const isExportDirFinEnabled = $('exportdirfin_checkbox').getProperty('checked');
        $('exportdirfin_text').setProperty('disabled', !isExportDirFinEnabled);
    };
-    var updateMailNotification = function() {
+    this.updateMailNotification = function() {
-        var isMailNotificationEnabled = $('mail_notification_checkbox').getProperty('checked');
+        const isMailNotificationEnabled = $('mail_notification_checkbox').getProperty('checked');
        $('src_email_txt').setProperty('disabled', !isMailNotificationEnabled);
        $('dest_email_txt').setProperty('disabled', !isMailNotificationEnabled);
        $('smtp_server_txt').setProperty('disabled', !isMailNotificationEnabled);
@ -1188,47 +1188,47 @@
        }
    };
-    var updateMailAuthSettings = function() {
+    this.updateMailAuthSettings = function() {
-        var isMailAuthEnabled = $('mail_auth_checkbox').getProperty('checked');
+        const isMailAuthEnabled = $('mail_auth_checkbox').getProperty('checked');
        $('mail_username_text').setProperty('disabled', !isMailAuthEnabled);
        $('mail_password_text').setProperty('disabled', !isMailAuthEnabled);
    };
-    var updateAutoRun = function() {
+    this.updateAutoRun = function() {
-        var isAutoRunEnabled = $('autorun_checkbox').getProperty('checked');
+        const isAutoRunEnabled = $('autorun_checkbox').getProperty('checked');
        $('autorunProg_txt').setProperty('disabled', !isAutoRunEnabled);
    };
    // Connection tab
-    var updateMaxConnecEnabled = function() {
+    this.updateMaxConnecEnabled = function() {
-        var isMaxConnecEnabled = $('max_connec_checkbox').getProperty('checked');
+        const isMaxConnecEnabled = $('max_connec_checkbox').getProperty('checked');
        $('max_connec_value').setProperty('disabled', !isMaxConnecEnabled);
    };
-    var updateMaxConnecPerTorrentEnabled = function() {
+    this.updateMaxConnecPerTorrentEnabled = function() {
-        var isMaxConnecPerTorrentEnabled = $('max_connec_per_torrent_checkbox').getProperty('checked');
+        const isMaxConnecPerTorrentEnabled = $('max_connec_per_torrent_checkbox').getProperty('checked');
        $('max_connec_per_torrent_value').setProperty('disabled', !isMaxConnecPerTorrentEnabled);
    };
-    var updateMaxUploadsEnabled = function() {
+    this.updateMaxUploadsEnabled = function() {
-        var isMaxUploadsEnabled = $('max_uploads_checkbox').getProperty('checked');
+        const isMaxUploadsEnabled = $('max_uploads_checkbox').getProperty('checked');
        $('max_uploads_value').setProperty('disabled', !isMaxUploadsEnabled);
    };
-    var updateMaxUploadsPerTorrentEnabled = function() {
+    this.updateMaxUploadsPerTorrentEnabled = function() {
-        var isMaxUploadsPerTorrentEnabled = $('max_uploads_per_torrent_checkbox').getProperty('checked');
+        const isMaxUploadsPerTorrentEnabled = $('max_uploads_per_torrent_checkbox').getProperty('checked');
        $('max_uploads_per_torrent_value').setProperty('disabled', !isMaxUploadsPerTorrentEnabled);
    };
-    var updatePeerProxySettings = function() {
+    this.updatePeerProxySettings = function() {
-        var isPeerProxyTypeSelected = $('peer_proxy_type_select').getProperty('value') != "none";
+        const isPeerProxyTypeSelected = $('peer_proxy_type_select').getProperty('value') != "none";
        $('peer_proxy_host_text').setProperty('disabled', !isPeerProxyTypeSelected);
        $('peer_proxy_port_value').setProperty('disabled', !isPeerProxyTypeSelected);
        $('use_peer_proxy_checkbox').setProperty('disabled', !isPeerProxyTypeSelected);
        $('proxy_only_for_torrents_checkbox').setProperty('disabled', !isPeerProxyTypeSelected);
        if (isPeerProxyTypeSelected) {
-            var isPeerProxyTypeSocks5 = $('peer_proxy_type_select').getProperty('value') == "socks5";
+            const isPeerProxyTypeSocks5 = $('peer_proxy_type_select').getProperty('value') == "socks5";
            $('peer_proxy_auth_checkbox').setProperty('disabled', !isPeerProxyTypeSocks5);
            if (!isPeerProxyTypeSocks5) {
@ -1243,22 +1243,22 @@
        }
    };
-    var updatePeerProxyAuthSettings = function() {
+    this.updatePeerProxyAuthSettings = function() {
-        var isPeerProxyAuthEnabled = $('peer_proxy_auth_checkbox').getProperty('checked');
+        const isPeerProxyAuthEnabled = $('peer_proxy_auth_checkbox').getProperty('checked');
        $('peer_proxy_username_text').setProperty('disabled', !isPeerProxyAuthEnabled);
        $('peer_proxy_password_text').setProperty('disabled', !isPeerProxyAuthEnabled);
    };
-    var updateFilterSettings = function() {
+    this.updateFilterSettings = function() {
-        var isIPFilterEnabled = $('ipfilter_enabled_checkbox').getProperty('checked');
+        const isIPFilterEnabled = $('ipfilter_enabled_checkbox').getProperty('checked');
        $('ipfilter_text').setProperty('disabled', !isIPFilterEnabled);
        $('ipfilter_trackers_checkbox').setProperty('disabled', !isIPFilterEnabled);
        $('banned_IPs_textarea').setProperty('disabled', !isIPFilterEnabled);
    };
    // Speed tab
-    var updateSchedulingEnabled = function() {
+    this.updateSchedulingEnabled = function() {
-        var isLimitSchedulingEnabled = $('limit_sheduling_checkbox').getProperty('checked');
+        const isLimitSchedulingEnabled = $('limit_sheduling_checkbox').getProperty('checked');
        $('schedule_from_hour').setProperty('disabled', !isLimitSchedulingEnabled);
        $('schedule_from_min').setProperty('disabled', !isLimitSchedulingEnabled);
        $('schedule_to_hour').setProperty('disabled', !isLimitSchedulingEnabled);
@ -1267,8 +1267,8 @@
    };
    // Bittorrent tab
-    var updateQueueingSystem = function() {
+    this.updateQueueingSystem = function() {
-        var isQueueingEnabled = $('queueing_checkbox').getProperty('checked');
+        const isQueueingEnabled = $('queueing_checkbox').getProperty('checked');
        $('max_active_dl_value').setProperty('disabled', !isQueueingEnabled);
        $('max_active_up_value').setProperty('disabled', !isQueueingEnabled);
        $('max_active_to_value').setProperty('disabled', !isQueueingEnabled);
@ -1276,59 +1276,59 @@
        updateSlowTorrentsSettings();
    };
-    var updateSlowTorrentsSettings = function() {
+    this.updateSlowTorrentsSettings = function() {
-        var isDontCountSlowTorrentsEnabled = (!$('dont_count_slow_torrents_checkbox').getProperty('disabled')) && $('dont_count_slow_torrents_checkbox').getProperty('checked');
+        const isDontCountSlowTorrentsEnabled = (!$('dont_count_slow_torrents_checkbox').getProperty('disabled')) && $('dont_count_slow_torrents_checkbox').getProperty('checked');
        $('dl_rate_threshold').setProperty('disabled', !isDontCountSlowTorrentsEnabled);
        $('ul_rate_threshold').setProperty('disabled', !isDontCountSlowTorrentsEnabled);
        $('torrent_inactive_timer').setProperty('disabled', !isDontCountSlowTorrentsEnabled);
    };
-    var updateMaxRatioTimeEnabled = function() {
+    this.updateMaxRatioTimeEnabled = function() {
-        var isMaxRatioEnabled = $('max_ratio_checkbox').getProperty('checked');
+        const isMaxRatioEnabled = $('max_ratio_checkbox').getProperty('checked');
        $('max_ratio_value').setProperty('disabled', !isMaxRatioEnabled);
-        var isMaxSeedingTimeEnabled = $('max_seeding_time_checkbox').getProperty('checked');
+        const isMaxSeedingTimeEnabled = $('max_seeding_time_checkbox').getProperty('checked');
        $('max_seeding_time_value').setProperty('disabled', !isMaxSeedingTimeEnabled);
        $('max_ratio_act').setProperty('disabled', !(isMaxRatioEnabled || isMaxSeedingTimeEnabled));
    };
-    var updateAddTrackersEnabled = function() {
+    this.updateAddTrackersEnabled = function() {
-        var isAddTrackersEnabled = $('add_trackers_checkbox').getProperty('checked');
+        const isAddTrackersEnabled = $('add_trackers_checkbox').getProperty('checked');
        $('add_trackers_textarea').setProperty('disabled', !isAddTrackersEnabled);
    };
    // Web UI tab
-    var updateHttpsSettings = function() {
+    this.updateHttpsSettings = function() {
-        var isUseHttpsEnabled = $('use_https_checkbox').getProperty('checked');
+        const isUseHttpsEnabled = $('use_https_checkbox').getProperty('checked');
        $('ssl_cert_text').setProperty('disabled', !isUseHttpsEnabled);
        $('ssl_key_text').setProperty('disabled', !isUseHttpsEnabled);
    };
-    var updateBypasssAuthSettings = function() {
+    this.updateBypasssAuthSettings = function() {
-        var isBypassAuthSubnetWhitelistEnabled = $('bypass_auth_subnet_whitelist_checkbox').getProperty('checked');
+        const isBypassAuthSubnetWhitelistEnabled = $('bypass_auth_subnet_whitelist_checkbox').getProperty('checked');
        $('bypass_auth_subnet_whitelist_textarea').setProperty('disabled', !isBypassAuthSubnetWhitelistEnabled);
    };
-    var updateAlternativeWebUISettings = function() {
+    this.updateAlternativeWebUISettings = function() {
-        var isUseAlternativeWebUIEnabled = $('use_alt_webui_checkbox').getProperty('checked');
+        const isUseAlternativeWebUIEnabled = $('use_alt_webui_checkbox').getProperty('checked');
        $('webui_files_location_textarea').setProperty('disabled', !isUseAlternativeWebUIEnabled);
    };
-    var updateHostHeaderValidationSettings = function() {
+    this.updateHostHeaderValidationSettings = function() {
-        var isHostHeaderValidationEnabled = $('host_header_validation_checkbox').getProperty('checked');
+        const isHostHeaderValidationEnabled = $('host_header_validation_checkbox').getProperty('checked');
        $('webui_domain_textarea').setProperty('disabled', !isHostHeaderValidationEnabled);
    };
-    var updateDynDnsSettings = function() {
+    this.updateDynDnsSettings = function() {
-        var isDynDnsEnabled = $('use_dyndns_checkbox').getProperty('checked');
+        const isDynDnsEnabled = $('use_dyndns_checkbox').getProperty('checked');
        $('dyndns_select').setProperty('disabled', !isDynDnsEnabled);
        $('dyndns_domain_text').setProperty('disabled', !isDynDnsEnabled);
        $('dyndns_username_text').setProperty('disabled', !isDynDnsEnabled);
        $('dyndns_password_text').setProperty('disabled', !isDynDnsEnabled);
    };
-    var registerDynDns = function() {
+    this.registerDynDns = function() {
        if ($('dyndns_select').getProperty('value').toInt() == 1) {
            window.open("http://www.no-ip.com/services/managed_dns/free_dynamic_dns.html", "NO-IP Registration");
        }
@ -1337,22 +1337,22 @@
        }
    };
-    var generateRandomPort = function() {
+    this.generateRandomPort = function() {
-        var min = 1024;
+        const min = 1024;
-        var max = 65535;
+        const max = 65535;
-        var port = Math.floor(Math.random() * (max - min + 1) + min);
+        const port = Math.floor(Math.random() * (max - min + 1) + min);
        $('port_value').setProperty('value', port);
    };
-    var time_padding = function(val) {
+    this.time_padding = function(val) {
-        var ret = val.toString();
+        let ret = val.toString();
        if (ret.length == 1)
            ret = '0' + ret;
        return ret;
    };
    // Advanced Tab
-    var updateNetworkInterfaces = function(default_iface) {
+    this.updateNetworkInterfaces = function(default_iface) {
        const url = 'api/v2/app/networkInterfaceList';
        $('networkInterface').empty();
        new Request.JSON({
@ -1374,7 +1374,7 @@
        }).send();
    };
-    var updateInterfaceAddresses = function(iface, default_addr) {
+    this.updateInterfaceAddresses = function(iface, default_addr) {
        const url = 'api/v2/app/networkInterfaceAddressList';
        $('optionalIPAddressToBind').empty();
        new Request.JSON({
@ -1399,8 +1399,8 @@
        }).send();
    }
-    var loadPreferences = function() {
+    this.loadPreferences = function() {
-        var url = 'api/v2/app/preferences';
+        const url = 'api/v2/app/preferences';
        new Request.JSON({
            url: url,
            method: 'get',
@ -1448,10 +1448,10 @@
                    updateExportDirFinEnabled();
                    // Automatically add torrents from
-                    var i = 0;
+                    let i = 0;
-                    for (var folder in pref.scan_dirs) {
+                    for (const folder in pref.scan_dirs) {
-                        var sel;
+                        let sel;
-                        var other = "";
+                        let other = "";
                        if (typeof pref.scan_dirs[folder] == "string") {
                            other = pref.scan_dirs[folder];
                            sel = "other";
@ -1486,7 +1486,7 @@
                    $('random_port_checkbox').setProperty('checked', pref.random_port);
                    // Connections Limits
-                    var max_connec = pref.max_connec.toInt();
+                    const max_connec = pref.max_connec.toInt();
                    if (max_connec <= 0) {
                        $('max_connec_checkbox').setProperty('checked', false);
                        $('max_connec_value').setProperty('value', 500);
@ -1496,7 +1496,7 @@
                        $('max_connec_value').setProperty('value', max_connec);
                    }
                    updateMaxConnecEnabled();
-                    var max_connec_per_torrent = pref.max_connec_per_torrent.toInt();
+                    const max_connec_per_torrent = pref.max_connec_per_torrent.toInt();
                    if (max_connec_per_torrent <= 0) {
                        $('max_connec_per_torrent_checkbox').setProperty('checked', false);
                        $('max_connec_per_torrent_value').setProperty('value', 100);
@ -1506,7 +1506,7 @@
                        $('max_connec_per_torrent_value').setProperty('value', max_connec_per_torrent);
                    }
                    updateMaxConnecPerTorrentEnabled();
-                    var max_uploads = pref.max_uploads.toInt();
+                    const max_uploads = pref.max_uploads.toInt();
                    if (max_uploads <= 0) {
                        $('max_uploads_checkbox').setProperty('checked', false);
                        $('max_uploads_value').setProperty('value', 8);
@ -1516,7 +1516,7 @@
                        $('max_uploads_value').setProperty('value', max_uploads);
                    }
                    updateMaxUploadsEnabled();
-                    var max_uploads_per_torrent = pref.max_uploads_per_torrent.toInt();
+                    const max_uploads_per_torrent = pref.max_uploads_per_torrent.toInt();
                    if (max_uploads_per_torrent <= 0) {
                        $('max_uploads_per_torrent_checkbox').setProperty('checked', false);
                        $('max_uploads_per_torrent_value').setProperty('value', 4);
@ -1587,7 +1587,7 @@
                    $('dht_checkbox').setProperty('checked', pref.dht);
                    $('pex_checkbox').setProperty('checked', pref.pex);
                    $('lsd_checkbox').setProperty('checked', pref.lsd);
-                    var encryption = pref.encryption.toInt();
+                    const encryption = pref.encryption.toInt();
                    $('encryption_select').getChildren('option')[encryption].setAttribute('selected', '');
                    $('anonymous_mode_checkbox').setProperty('checked', pref.anonymous_mode);
@ -1608,14 +1608,12 @@
                        $('max_ratio_value').setProperty('value', pref.max_ratio);
                    else
                        $('max_ratio_value').setProperty('value', 1);
                    var max_ratio_act = pref.max_ratio_act.toInt();
                    $('max_ratio_act').getChildren('option')[max_ratio_act].setAttribute('selected', '');
                    $('max_seeding_time_checkbox').setProperty('checked', pref.max_seeding_time_enabled);
                    if (pref.max_seeding_time_enabled)
                        $('max_seeding_time_value').setProperty('value', pref.max_seeding_time.toInt());
                    else
                        $('max_seeding_time_value').setProperty('value', 1440);
-                    var max_ratio_act = pref.max_ratio_act.toInt();
+                    const max_ratio_act = pref.max_ratio_act.toInt();
                    $('max_ratio_act').getChildren('option')[max_ratio_act].setAttribute('selected', '');
                    updateMaxRatioTimeEnabled();
@ -1703,8 +1701,8 @@
        }).send();
    };
-    var applyPreferences = function() {
+    this.applyPreferences = function() {
-        var settings = new Hash();
+        const settings = new Hash();
        // Validate form data
        // Downloads tab
        // When adding a torrent
@ -1751,7 +1749,7 @@
        // Connection tab
        // Listening Port
-        var listen_port = $('port_value').getProperty('value').toInt();
+        const listen_port = $('port_value').getProperty('value').toInt();
        if (isNaN(listen_port) || listen_port < 1 || listen_port > 65535) {
            alert("QBT_TR(The port used for incoming connections must be between 1 and 65535.)QBT_TR[CONTEXT=HttpServer]");
            return;
@ -1761,7 +1759,7 @@
        settings.set('random_port', $('random_port_checkbox').getProperty('checked'));
        // Connections Limits
-        var max_connec = -1;
+        let max_connec = -1;
        if ($('max_connec_checkbox').getProperty('checked')) {
            max_connec = $('max_connec_value').getProperty('value').toInt();
            if (isNaN(max_connec) || max_connec <= 0) {
@ -1770,7 +1768,7 @@
            }
        }
        settings.set('max_connec', max_connec);
-        var max_connec_per_torrent = -1;
+        let max_connec_per_torrent = -1;
        if ($('max_connec_per_torrent_checkbox').getProperty('checked')) {
            max_connec_per_torrent = $('max_connec_per_torrent_value').getProperty('value').toInt();
            if (isNaN(max_connec_per_torrent) || max_connec_per_torrent <= 0) {
@ -1779,7 +1777,7 @@
            }
        }
        settings.set('max_connec_per_torrent', max_connec_per_torrent);
-        var max_uploads = -1;
+        let max_uploads = -1;
        if ($('max_uploads_checkbox').getProperty('checked')) {
            max_uploads = $('max_uploads_value').getProperty('value').toInt();
            if (isNaN(max_uploads) || max_uploads <= 0) {
@ -1788,7 +1786,7 @@
            }
        }
        settings.set('max_uploads', max_uploads);
-        var max_uploads_per_torrent = -1;
+        let max_uploads_per_torrent = -1;
        if ($('max_uploads_per_torrent_checkbox').getProperty('checked')) {
            max_uploads_per_torrent = $('max_uploads_per_torrent_value').getProperty('value').toInt();
            if (isNaN(max_uploads_per_torrent) || max_uploads_per_torrent <= 0) {
@ -1799,9 +1797,9 @@
        settings.set('max_uploads_per_torrent', max_uploads_per_torrent);
        // Proxy Server
-        var proxy_type_str = $('peer_proxy_type_select').getProperty('value');
+        const proxy_type_str = $('peer_proxy_type_select').getProperty('value');
-        var proxy_type = 0;
+        let proxy_type = 0;
-        var proxy_auth_enabled = false;
+        let proxy_auth_enabled = false;
        if (proxy_type_str == "socks5") {
            if ($('peer_proxy_auth_checkbox').getProperty('checked')) {
                proxy_type = 4;
@ -1844,14 +1842,14 @@
        // Speed tab
        // Global Rate Limits
-        var up_limit = $('up_limit_value').getProperty('value').toInt() * 1024;
+        const up_limit = $('up_limit_value').getProperty('value').toInt() * 1024;
        if (isNaN(up_limit) || up_limit < 0) {
            alert("QBT_TR(Global upload rate limit must be greater than 0 or disabled.)QBT_TR[CONTEXT=HttpServer]");
            return;
        }
        settings.set('up_limit', up_limit);
-        var dl_limit = $('dl_limit_value').getProperty('value').toInt() * 1024;
+        const dl_limit = $('dl_limit_value').getProperty('value').toInt() * 1024;
        if (isNaN(dl_limit) || dl_limit < 0) {
            alert("QBT_TR(Global download rate limit must be greater than 0 or disabled.)QBT_TR[CONTEXT=HttpServer]");
            return;
@ -1859,14 +1857,14 @@
        settings.set('dl_limit', dl_limit);
        // Alternative Global Rate Limits
-        var alt_up_limit = $('alt_up_limit_value').getProperty('value').toInt() * 1024;
+        const alt_up_limit = $('alt_up_limit_value').getProperty('value').toInt() * 1024;
        if (isNaN(alt_up_limit) || alt_up_limit < 0) {
            alert("QBT_TR(Alternative upload rate limit must be greater than 0 or disabled.)QBT_TR[CONTEXT=HttpServer]");
            return;
        }
        settings.set('alt_up_limit', alt_up_limit);
-        var alt_dl_limit = $('alt_dl_limit_value').getProperty('value').toInt() * 1024;
+        const alt_dl_limit = $('alt_dl_limit_value').getProperty('value').toInt() * 1024;
        if (isNaN(alt_dl_limit) || alt_dl_limit < 0) {
            alert("QBT_TR(Alternative download rate limit must be greater than 0 or disabled.)QBT_TR[CONTEXT=HttpServer]");
            return;
@ -1879,7 +1877,7 @@
        settings.set('limit_lan_peers', $('limit_lan_peers_checkbox').getProperty('checked'));
        // Scheduler
-        var scheduling_enabled = $('limit_sheduling_checkbox').getProperty('checked');
+        const scheduling_enabled = $('limit_sheduling_checkbox').getProperty('checked');
        settings.set('scheduler_enabled', scheduling_enabled);
        if (scheduling_enabled) {
            settings.set('schedule_from_hour', $('schedule_from_hour').getProperty('value').toInt());
@ -1900,38 +1898,38 @@
        // Torrent Queueing
        settings.set('queueing_enabled', $('queueing_checkbox').getProperty('checked'));
        if ($('queueing_checkbox').getProperty('checked')) {
-            var max_active_downloads = $('max_active_dl_value').getProperty('value').toInt();
+            const max_active_downloads = $('max_active_dl_value').getProperty('value').toInt();
            if (isNaN(max_active_downloads) || max_active_downloads < -1) {
                alert("QBT_TR(Maximum active downloads must be greater than -1.)QBT_TR[CONTEXT=HttpServer]");
                return;
            }
            settings.set('max_active_downloads', max_active_downloads);
-            var max_active_uploads = $('max_active_up_value').getProperty('value').toInt();
+            const max_active_uploads = $('max_active_up_value').getProperty('value').toInt();
            if (isNaN(max_active_uploads) || max_active_uploads < -1) {
                alert("QBT_TR(Maximum active uploads must be greater than -1.)QBT_TR[CONTEXT=HttpServer]");
                return;
            }
            settings.set('max_active_uploads', max_active_uploads);
-            var max_active_torrents = $('max_active_to_value').getProperty('value').toInt();
+            const max_active_torrents = $('max_active_to_value').getProperty('value').toInt();
            if (isNaN(max_active_torrents) || max_active_torrents < -1) {
                alert("QBT_TR(Maximum active torrents must be greater than -1.)QBT_TR[CONTEXT=HttpServer]");
                return;
            }
            settings.set('max_active_torrents', max_active_torrents);
            settings.set('dont_count_slow_torrents', $('dont_count_slow_torrents_checkbox').getProperty('checked'));
-            var dl_rate_threshold = $('dl_rate_threshold').getProperty('value').toInt();
+            const dl_rate_threshold = $('dl_rate_threshold').getProperty('value').toInt();
            if (isNaN(dl_rate_threshold) || (dl_rate_threshold < 1)) {
                alert("QBT_TR(Download rate threshold must be greater than 0.)QBT_TR[CONTEXT=HttpServer]");
                return;
            }
            settings.set('slow_torrent_dl_rate_threshold', dl_rate_threshold);
-            var ul_rate_threshold = $('ul_rate_threshold').getProperty('value').toInt();
+            const ul_rate_threshold = $('ul_rate_threshold').getProperty('value').toInt();
            if (isNaN(ul_rate_threshold) || (ul_rate_threshold < 1)) {
                alert("QBT_TR(Upload rate threshold must be greater than 0.)QBT_TR[CONTEXT=HttpServer]");
                return;
            }
            settings.set('slow_torrent_ul_rate_threshold', ul_rate_threshold);
-            var torrent_inactive_timer = $('torrent_inactive_timer').getProperty('value').toInt();
+            const torrent_inactive_timer = $('torrent_inactive_timer').getProperty('value').toInt();
            if (isNaN(torrent_inactive_timer) || (torrent_inactive_timer < 1)) {
                alert("QBT_TR(Torrent inactivity timer must be greater than 0.)QBT_TR[CONTEXT=HttpServer]");
                return;
@ -1940,7 +1938,7 @@
        }
        // Share Ratio Limiting
-        var max_ratio = -1;
+        let max_ratio = -1;
        if ($('max_ratio_checkbox').getProperty('checked')) {
            max_ratio = $('max_ratio_value').getProperty('value');
            if (isNaN(max_ratio) || max_ratio < 0 || max_ratio > 9998) {
@ -1952,7 +1950,7 @@
        settings.set('max_ratio', max_ratio);
        settings.set('max_ratio_act', $('max_ratio_act').getProperty('value').toInt());
-        var max_seeding_time = -1;
+        let max_seeding_time = -1;
        if ($('max_seeding_time_checkbox').getProperty('checked')) {
            max_seeding_time = $('max_seeding_time_value').getProperty('value').toInt();
            if (isNaN(max_seeding_time) || max_seeding_time < 0 || max_seeding_time > 525600) {
@ -1974,8 +1972,8 @@
        // HTTP Server
        settings.set('web_ui_domain_list', $('webui_domain_textarea').getProperty('value'));
-        var web_ui_address = $('webui_address_value').getProperty('value').toString();
+        const web_ui_address = $('webui_address_value').getProperty('value').toString();
-        var web_ui_port = $('webui_port_value').getProperty('value').toInt();
+        const web_ui_port = $('webui_port_value').getProperty('value').toInt();
        if (isNaN(web_ui_port) || web_ui_port < 1 || web_ui_port > 65535) {
            alert("QBT_TR(The port used for the Web UI must be between 1 and 65535.)QBT_TR[CONTEXT=HttpServer]");
            return;
@ -1988,12 +1986,12 @@
        settings.set('web_ui_https_key_path', $('ssl_key_text').getProperty('value'));
        // Authentication
-        var web_ui_username = $('webui_username_text').getProperty('value');
+        const web_ui_username = $('webui_username_text').getProperty('value');
        if (web_ui_username.length < 3) {
            alert("QBT_TR(The Web UI username must be at least 3 characters long.)QBT_TR[CONTEXT=OptionsDialog]");
            return;
        }
-        var web_ui_password = $('webui_password_text').getProperty('value');
+        const web_ui_password = $('webui_password_text').getProperty('value');
        if ((0 < web_ui_password.length) && (web_ui_password.length < 6)) {
            alert("QBT_TR(The Web UI password must be at least 6 characters long.)QBT_TR[CONTEXT=OptionsDialog]");
            return;
@ -2008,8 +2006,8 @@
        settings.set('web_ui_session_timeout', $('webUISessionTimeoutInput').getProperty('value'));
        // Use alternative Web UI
-        var alternative_webui_enabled = $('use_alt_webui_checkbox').getProperty('checked');
+        const alternative_webui_enabled = $('use_alt_webui_checkbox').getProperty('checked');
-        var webui_files_location_textarea = $('webui_files_location_textarea').getProperty('value');
+        const webui_files_location_textarea = $('webui_files_location_textarea').getProperty('value');
        if (alternative_webui_enabled && (webui_files_location_textarea.trim() === "")) {
            alert("QBT_TR(The alternative Web UI files location cannot be blank.)QBT_TR[CONTEXT=OptionsDialog]");
            return;
@ -2064,7 +2062,7 @@
        settings.set('announce_ip', $('announceIP').getProperty('value'));
        // Send it to qBT
-        var json_str = JSON.encode(settings);
+        const json_str = JSON.encode(settings);
        new Request({
            url: 'api/v2/app/setPreferences',
--- a/src/webui/www/private/properties_content.html
+++ b/src/webui/www/private/properties_content.html
@ -155,7 +155,7 @@
 <script>
    'use strict';
-    var selectedTab = $(getLocalStorageItem('selected_tab', 'PropGeneralLink'));
+    const selectedTab = $(getLocalStorageItem('selected_tab', 'PropGeneralLink'));
    if (selectedTab)
        selectedTab.click();
 </script>
--- a/src/webui/www/private/rename.html
+++ b/src/webui/www/private/rename.html
@ -30,7 +30,7 @@
        }).activate();
        window.addEvent('domready', function() {
-            var name = new URI().getData('name');
+            const name = new URI().getData('name');
            // set text field to current value
            if (name)
                $('rename').value = decodeURIComponent(name);
@ -39,11 +39,11 @@
            $('renameButton').addEvent('click', function(e) {
                new Event(e).stop();
                // check field
-                var name = $('rename').value.trim();
+                const name = $('rename').value.trim();
                if (name === null || name === "")
                    return false;
-                var hash = new URI().getData('hash');
+                const hash = new URI().getData('hash');
                if (hash) {
                    new Request({
                        url: 'api/v2/torrents/rename',
--- a/src/webui/www/private/scripts/client.js
+++ b/src/webui/www/private/scripts/client.js
@ -24,36 +24,36 @@
 'use strict';
-var torrentsTable = new TorrentsTable();
+this.torrentsTable = new TorrentsTable();
-var torrentTrackersTable = new TorrentTrackersTable();
+const torrentTrackersTable = new TorrentTrackersTable();
-var torrentPeersTable = new TorrentPeersTable();
+const torrentPeersTable = new TorrentPeersTable();
-var torrentFilesTable = new TorrentFilesTable();
+const torrentFilesTable = new TorrentFilesTable();
-var searchResultsTable = new SearchResultsTable();
+const searchResultsTable = new SearchResultsTable();
-var searchPluginsTable = new SearchPluginsTable();
+const searchPluginsTable = new SearchPluginsTable();
-var updatePropertiesPanel = function() {};
+let updatePropertiesPanel = function() {};
-var updateTorrentData = function() {};
+let updateTorrentData = function() {};
-var updateTrackersData = function() {};
+let updateTrackersData = function() {};
-var updateTorrentPeersData = function() {};
+let updateTorrentPeersData = function() {};
-var updateWebSeedsData = function() {};
+let updateWebSeedsData = function() {};
-var updateTorrentFilesData = function() {};
+let updateTorrentFilesData = function() {};
-var updateMainData = function() {};
+this.updateMainData = function() {};
-var alternativeSpeedLimits = false;
+let alternativeSpeedLimits = false;
-var queueing_enabled = true;
+let queueing_enabled = true;
-var serverSyncMainDataInterval = 1500;
+let serverSyncMainDataInterval = 1500;
-var customSyncMainDataInterval = null;
+let customSyncMainDataInterval = null;
-var clipboardEvent;
+let clipboardEvent;
-var CATEGORIES_ALL = 1;
+const CATEGORIES_ALL = 1;
-var CATEGORIES_UNCATEGORIZED = 2;
+const CATEGORIES_UNCATEGORIZED = 2;
-var category_list = {};
+let category_list = {};
-var selected_category = CATEGORIES_ALL;
+let selected_category = CATEGORIES_ALL;
-var setCategoryFilter = function() {};
+let setCategoryFilter = function() {};
 const TAGS_ALL = 1;
 const TAGS_UNTAGGED = 2;
@ -63,11 +63,11 @@ let tagList = {};
 let selectedTag = TAGS_ALL;
 let setTagFilter = function() {};
-var selected_filter = getLocalStorageItem('selected_filter', 'all');
+let selected_filter = getLocalStorageItem('selected_filter', 'all');
-var setFilter = function() {};
+let setFilter = function() {};
-var toggleFilterDisplay = function() {};
+let toggleFilterDisplay = function() {};
-var loadSelectedCategory = function() {
+const loadSelectedCategory = function() {
    selected_category = getLocalStorageItem('selected_category', CATEGORIES_ALL);
 };
 loadSelectedCategory();
@ -78,9 +78,9 @@ const loadSelectedTag = function() {
 loadSelectedTag();
 function genHash(string) {
-    var hash = 0;
+    let hash = 0;
-    for (var i = 0; i < string.length; ++i) {
+    for (let i = 0; i < string.length; ++i) {
-        var c = string.charCodeAt(i);
+        const c = string.charCodeAt(i);
        hash = (c + hash * 31) | 0;
    }
    return hash;
@ -111,9 +111,9 @@ const qbtVersion = function() {
 window.addEvent('load', function() {
-    var saveColumnSizes = function() {
+    const saveColumnSizes = function() {
-        var filters_width = $('Filters').getSize().x;
+        const filters_width = $('Filters').getSize().x;
-        var properties_height_rel = $('propertiesPanel').getSize().y / Window.getSize().y;
+        const properties_height_rel = $('propertiesPanel').getSize().y / Window.getSize().y;
        localStorage.setItem('filters_width', filters_width);
        localStorage.setItem('properties_height_rel', properties_height_rel);
    };
@ -131,8 +131,8 @@ window.addEvent('load', function() {
    });*/
    MochaUI.Desktop.initialize();
-    var buildTransfersTab = function() {
+    const buildTransfersTab = function() {
-        var filt_w = localStorage.getItem('filters_width');
+        let filt_w = localStorage.getItem('filters_width');
        if ($defined(filt_w))
            filt_w = filt_w.toInt();
        else
@ -151,7 +151,7 @@ window.addEvent('load', function() {
        });
    };
-    var buildSearchTab = function() {
+    const buildSearchTab = function() {
        new MochaUI.Column({
            id: 'searchTabColumn',
            placement: 'main',
@ -202,11 +202,11 @@ window.addEvent('load', function() {
    };
    toggleFilterDisplay = function(filter) {
-        var element = filter + "FilterList";
+        const element = filter + "FilterList";
        localStorage.setItem('filter_' + filter + "_collapsed", !$(element).hasClass("invisible"));
        $(element).toggleClass("invisible")
-        var parent = $(element).getParent(".filterWrapper");
+        const parent = $(element).getParent(".filterWrapper");
-        var toggleIcon = $(parent).getChildren(".filterTitle img");
+        const toggleIcon = $(parent).getChildren(".filterTitle img");
        if (toggleIcon)
            toggleIcon[0].toggleClass("rotate");
    };
@ -232,7 +232,7 @@ window.addEvent('load', function() {
    initializeWindows();
    // Show Top Toolbar is enabled by default
-    var showTopToolbar = true;
+    let showTopToolbar = true;
    if (localStorage.getItem('show_top_toolbar') !== null)
        showTopToolbar = localStorage.getItem('show_top_toolbar') == "true";
    if (!showTopToolbar) {
@ -241,7 +241,7 @@ window.addEvent('load', function() {
    }
    // Show Status Bar is enabled by default
-    var showStatusBar = true;
+    let showStatusBar = true;
    if (localStorage.getItem('show_status_bar') !== null)
        showStatusBar = localStorage.getItem('show_status_bar') === "true";
    if (!showStatusBar) {
@ -249,12 +249,12 @@ window.addEvent('load', function() {
        $('desktopFooterWrapper').addClass('invisible');
    }
-    var speedInTitle = localStorage.getItem('speed_in_browser_title_bar') == "true";
+    let speedInTitle = localStorage.getItem('speed_in_browser_title_bar') == "true";
    if (!speedInTitle)
        $('speedInBrowserTitleBarLink').firstChild.style.opacity = '0';
    // After showing/hiding the toolbar + status bar
-    var showSearchEngine = localStorage.getItem('show_search_engine') === "true";
+    let showSearchEngine = localStorage.getItem('show_search_engine') === "true";
    if (!showSearchEngine) {
        // uncheck menu option
        $('showSearchEngineLink').firstChild.style.opacity = '0';
@ -265,13 +265,13 @@ window.addEvent('load', function() {
    // After Show Top Toolbar
    MochaUI.Desktop.setDesktopSize();
-    var syncMainDataLastResponseId = 0;
+    let syncMainDataLastResponseId = 0;
-    var serverState = {};
+    const serverState = {};
-    var removeTorrentFromCategoryList = function(hash) {
+    const removeTorrentFromCategoryList = function(hash) {
        if (hash === null || hash === "")
            return false;
-        var removed = false;
+        let removed = false;
        Object.each(category_list, function(category) {
            if (Object.contains(category.torrents, hash)) {
                removed = true;
@ -281,15 +281,15 @@ window.addEvent('load', function() {
        return removed;
    };
-    var addTorrentToCategoryList = function(torrent) {
+    const addTorrentToCategoryList = function(torrent) {
-        var category = torrent['category'];
+        const category = torrent['category'];
        if (typeof category === 'undefined')
            return false;
        if (category.length === 0) { // Empty category
            removeTorrentFromCategoryList(torrent['hash']);
            return true;
        }
-        var categoryHash = genHash(category);
+        const categoryHash = genHash(category);
        if (category_list[categoryHash] === null) // This should not happen
            category_list[categoryHash] = {
                name: category,
@ -339,11 +339,11 @@ window.addEvent('load', function() {
        return added;
    };
-    var updateFilter = function(filter, filterTitle) {
+    const updateFilter = function(filter, filterTitle) {
        $(filter + '_filter').firstChild.childNodes[1].nodeValue = filterTitle.replace('%1', torrentsTable.getFilteredTorrentsNumber(filter, CATEGORIES_ALL, TAGS_ALL));
    };
-    var updateFiltersList = function() {
+    const updateFiltersList = function() {
        updateFilter('all', 'QBT_TR(All (%1))QBT_TR[CONTEXT=StatusFilterWidget]');
        updateFilter('downloading', 'QBT_TR(Downloading (%1))QBT_TR[CONTEXT=StatusFilterWidget]');
        updateFilter('seeding', 'QBT_TR(Seeding (%1))QBT_TR[CONTEXT=StatusFilterWidget]');
@ -355,17 +355,17 @@ window.addEvent('load', function() {
        updateFilter('errored', 'QBT_TR(Errored (%1))QBT_TR[CONTEXT=StatusFilterWidget]');
    };
-    var updateCategoryList = function() {
+    const updateCategoryList = function() {
-        var categoryList = $('categoryFilterList');
+        const categoryList = $('categoryFilterList');
        if (!categoryList)
            return;
        categoryList.empty();
-        var create_link = function(hash, text, count) {
+        const create_link = function(hash, text, count) {
-            var html = '<a href="#" onclick="setCategoryFilter(' + hash + ');return false;">'
+            const html = '<a href="#" onclick="setCategoryFilter(' + hash + ');return false;">'
                + '<img src="images/qbt-theme/inode-directory.svg"/>'
                + escapeHtml(text) + ' (' + count + ')' + '</a>';
-            var el = new Element('li', {
+            const el = new Element('li', {
                id: hash,
                html: html
            });
@ -373,8 +373,8 @@ window.addEvent('load', function() {
            return el;
        };
-        var all = torrentsTable.getRowIds().length;
+        const all = torrentsTable.getRowIds().length;
-        var uncategorized = 0;
+        let uncategorized = 0;
        Object.each(torrentsTable.rows, function(row) {
            if (row['full_data'].category.length === 0)
                uncategorized += 1;
@ -382,27 +382,27 @@ window.addEvent('load', function() {
        categoryList.appendChild(create_link(CATEGORIES_ALL, 'QBT_TR(All)QBT_TR[CONTEXT=CategoryFilterModel]', all));
        categoryList.appendChild(create_link(CATEGORIES_UNCATEGORIZED, 'QBT_TR(Uncategorized)QBT_TR[CONTEXT=CategoryFilterModel]', uncategorized));
-        var sortedCategories = [];
+        const sortedCategories = [];
        Object.each(category_list, function(category) {
            sortedCategories.push(category.name);
        });
        sortedCategories.sort();
        Object.each(sortedCategories, function(categoryName) {
-            var categoryHash = genHash(categoryName);
+            const categoryHash = genHash(categoryName);
-            var categoryCount = category_list[categoryHash].torrents.length;
+            const categoryCount = category_list[categoryHash].torrents.length;
            categoryList.appendChild(create_link(categoryHash, categoryName, categoryCount));
        });
        highlightSelectedCategory();
    };
-    var highlightSelectedCategory = function() {
+    const highlightSelectedCategory = function() {
-        var categoryList = $('categoryFilterList');
+        const categoryList = $('categoryFilterList');
        if (!categoryList)
            return;
-        var childrens = categoryList.childNodes;
+        const childrens = categoryList.childNodes;
-        for (var i = 0; i < childrens.length; ++i) {
+        for (let i = 0; i < childrens.length; ++i) {
            if (childrens[i].id == selected_category)
                childrens[i].className = "selectedFilter";
            else
@ -464,16 +464,16 @@ window.addEvent('load', function() {
            children[i].className = (children[i].id === selectedTag) ? "selectedFilter" : "";
    };
-    var syncMainDataTimer;
+    let syncMainDataTimer;
-    var syncMainData = function() {
+    const syncMainData = function() {
-        var url = new URI('api/v2/sync/maindata');
+        const url = new URI('api/v2/sync/maindata');
        url.setData('rid', syncMainDataLastResponseId);
        new Request.JSON({
            url: url,
            noCache: true,
            method: 'get',
            onFailure: function() {
-                var errorDiv = $('error_div');
+                const errorDiv = $('error_div');
                if (errorDiv)
                    errorDiv.set('html', 'QBT_TR(qBittorrent client is not reachable)QBT_TR[CONTEXT=HttpServer]');
                clearTimeout(syncMainDataTimer);
@ -483,10 +483,10 @@ window.addEvent('load', function() {
                $('error_div').set('html', '');
                if (response) {
                    clearTimeout(torrentsFilterInputTimer);
-                    var torrentsTableSelectedRows;
+                    let torrentsTableSelectedRows;
-                    var update_categories = false;
+                    let update_categories = false;
                    let updateTags = false;
-                    var full_update = (response['full_update'] === true);
+                    const full_update = (response['full_update'] === true);
                    if (full_update) {
                        torrentsTableSelectedRows = torrentsTable.selectedRowsIds();
                        torrentsTable.clear();
@ -497,9 +497,9 @@ window.addEvent('load', function() {
                        syncMainDataLastResponseId = response['rid'];
                    }
                    if (response['categories']) {
-                        for (var key in response['categories']) {
+                        for (const key in response['categories']) {
-                            var category = response['categories'][key];
+                            const category = response['categories'][key];
-                            var categoryHash = genHash(key);
+                            const categoryHash = genHash(key);
                            if (category_list[categoryHash] !== undefined) {
                                // only the save path can change for existing categories
                                category_list[categoryHash].savePath = category.savePath;
@ -516,7 +516,7 @@ window.addEvent('load', function() {
                    }
                    if (response['categories_removed']) {
                        response['categories_removed'].each(function(category) {
-                            var categoryHash = genHash(category);
+                            const categoryHash = genHash(category);
                            delete category_list[categoryHash];
                        });
                        update_categories = true;
@ -541,8 +541,8 @@ window.addEvent('load', function() {
                        updateTags = true;
                    }
                    if (response['torrents']) {
-                        var updateTorrentList = false;
+                        let updateTorrentList = false;
-                        for (var key in response['torrents']) {
+                        for (const key in response['torrents']) {
                            response['torrents'][key]['hash'] = key;
                            response['torrents'][key]['rowId'] = key;
                            if (response['torrents'][key]['state'])
@ -570,8 +570,8 @@ window.addEvent('load', function() {
                    torrentsTable.updateTable(full_update);
                    torrentsTable.altRow();
                    if (response['server_state']) {
-                        var tmp = response['server_state'];
+                        const tmp = response['server_state'];
-                        for (var k in tmp)
+                        for (const k in tmp)
                            serverState[k] = tmp[k];
                        processServerState();
                    }
@ -601,8 +601,8 @@ window.addEvent('load', function() {
        syncMainDataTimer = syncMainData.delay(100);
    };
-    var processServerState = function() {
+    const processServerState = function() {
-        var transfer_info = friendlyUnit(serverState.dl_info_speed, true);
+        let transfer_info = friendlyUnit(serverState.dl_info_speed, true);
        if (serverState.dl_rate_limit > 0)
            transfer_info += " [" + friendlyUnit(serverState.dl_rate_limit, true) + "]";
        transfer_info += " (" + friendlyUnit(serverState.dl_info_data, false) + ")";
@ -674,7 +674,7 @@ window.addEvent('load', function() {
        serverSyncMainDataInterval = Math.max(serverState.refresh_interval, 500);
    };
-    var updateAltSpeedIcon = function(enabled) {
+    const updateAltSpeedIcon = function(enabled) {
        if (enabled)
            $('alternativeSpeedLimits').src = "images/slow.svg";
        else
@ -768,7 +768,7 @@ window.addEvent('load', function() {
    // main window tabs
-    var showTransfersTab = function() {
+    const showTransfersTab = function() {
        $("filtersColumn").removeClass("invisible");
        $("filtersColumn_handle").removeClass("invisible");
        $("mainColumn").removeClass("invisible");
@ -780,35 +780,35 @@ window.addEvent('load', function() {
        hideSearchTab();
    };
-    var hideTransfersTab = function() {
+    const hideTransfersTab = function() {
        $("filtersColumn").addClass("invisible");
        $("filtersColumn_handle").addClass("invisible");
        $("mainColumn").addClass("invisible");
        MochaUI.Desktop.resizePanels();
    };
-    var showSearchTab = function() {
+    const showSearchTab = function() {
        $("searchTabColumn").removeClass("invisible");
        customSyncMainDataInterval = 30000;
        hideTransfersTab();
    };
-    var hideSearchTab = function() {
+    const hideSearchTab = function() {
        $("searchTabColumn").addClass("invisible");
        MochaUI.Desktop.resizePanels();
    };
-    var addMainWindowTabsEventListener = function() {
+    const addMainWindowTabsEventListener = function() {
        $('transfersTabLink').addEvent('click', showTransfersTab);
        $('searchTabLink').addEvent('click', showSearchTab);
    };
-    var removeMainWindowTabsEventListener = function() {
+    const removeMainWindowTabsEventListener = function() {
        $('transfersTabLink').removeEvent('click', showTransfersTab);
        $('searchTabLink').removeEvent('click', showSearchTab);
    };
-    var addSearchPanel = function() {
+    const addSearchPanel = function() {
        new MochaUI.Panel({
            id: 'SearchPanel',
            title: 'Search',
@ -847,7 +847,7 @@ window.addEvent('load', function() {
        onResize: saveColumnSizes,
        height: null
    });
-    var prop_h = localStorage.getItem('properties_height_rel');
+    let prop_h = localStorage.getItem('properties_height_rel');
    if ($defined(prop_h))
        prop_h = prop_h.toFloat() * Window.getSize().y;
    else
@ -927,11 +927,11 @@ window.addEvent('load', function() {
        height: prop_h
    });
-    var prevTorrentsFilterValue;
+    let prevTorrentsFilterValue;
-    var torrentsFilterInputTimer = null;
+    let torrentsFilterInputTimer = null;
    // listen for changes to torrentsFilterInput
    $('torrentsFilterInput').addEvent('input', function() {
-        var value = $('torrentsFilterInput').get("value");
+        const value = $('torrentsFilterInput').get("value");
        if (value !== prevTorrentsFilterValue) {
            prevTorrentsFilterValue = value;
            clearTimeout(torrentsFilterInputTimer);
--- a/src/webui/www/private/scripts/contextmenu.js
+++ b/src/webui/www/private/scripts/contextmenu.js
@ -28,8 +28,8 @@
 'use strict';
-var lastShownContexMenu = null;
+let lastShownContexMenu = null;
-var ContextMenu = new Class({
+const ContextMenu = new Class({
    //implements
    Implements: [Options, Events],
@ -87,7 +87,7 @@ var ContextMenu = new Class({
    adjustMenuPosition: function(e) {
        this.updateMenuItems();
-        var scrollableMenuMaxHeight = document.documentElement.clientHeight * 0.75;
+        const scrollableMenuMaxHeight = document.documentElement.clientHeight * 0.75;
        if (this.menu.hasClass('scrollableMenu'))
            this.menu.setStyle('max-height', scrollableMenuMaxHeight);
@ -99,8 +99,8 @@ var ContextMenu = new Class({
        });
        // position the menu
-        var xPosMenu = e.page.x + this.options.offsets.x;
+        let xPosMenu = e.page.x + this.options.offsets.x;
-        var yPosMenu = e.page.y + this.options.offsets.y;
+        let yPosMenu = e.page.y + this.options.offsets.y;
        if (xPosMenu + this.menu.offsetWidth > document.documentElement.clientWidth)
            xPosMenu -= this.menu.offsetWidth;
        if (yPosMenu + this.menu.offsetHeight > document.documentElement.clientHeight)
@ -117,16 +117,16 @@ var ContextMenu = new Class({
        });
        // position the sub-menu
-        var uls = this.menu.getElementsByTagName('ul');
+        const uls = this.menu.getElementsByTagName('ul');
-        for (var i = 0; i < uls.length; ++i) {
+        for (let i = 0; i < uls.length; ++i) {
-            var ul = uls[i];
+            const ul = uls[i];
            if (ul.hasClass('scrollableMenu'))
                ul.setStyle('max-height', scrollableMenuMaxHeight);
-            var rectParent = ul.parentNode.getBoundingClientRect();
+            const rectParent = ul.parentNode.getBoundingClientRect();
-            var xPosOrigin = rectParent.left;
+            const xPosOrigin = rectParent.left;
-            var yPosOrigin = rectParent.bottom;
+            const yPosOrigin = rectParent.bottom;
-            var xPos = xPosOrigin + rectParent.width - 1;
+            let xPos = xPosOrigin + rectParent.width - 1;
-            var yPos = yPosOrigin - rectParent.height - 1;
+            let yPos = yPosOrigin - rectParent.height - 1;
            if (xPos + ul.offsetWidth > document.documentElement.clientWidth)
                xPos -= (ul.offsetWidth + rectParent.width - 2);
            if (yPos + ul.offsetHeight > document.documentElement.clientHeight)
@ -277,27 +277,27 @@ var ContextMenu = new Class({
    }
 });
-var TorrentsTableContextMenu = new Class({
+const TorrentsTableContextMenu = new Class({
    Extends: ContextMenu,
    updateMenuItems: function() {
-        var all_are_seq_dl = true;
+        let all_are_seq_dl = true;
-        var there_are_seq_dl = false;
+        let there_are_seq_dl = false;
-        var all_are_f_l_piece_prio = true;
+        let all_are_f_l_piece_prio = true;
-        var there_are_f_l_piece_prio = false;
+        let there_are_f_l_piece_prio = false;
-        var all_are_downloaded = true;
+        let all_are_downloaded = true;
-        var all_are_paused = true;
+        let all_are_paused = true;
-        var there_are_paused = false;
+        let there_are_paused = false;
-        var all_are_force_start = true;
+        let all_are_force_start = true;
-        var there_are_force_start = false;
+        let there_are_force_start = false;
-        var all_are_super_seeding = true;
+        let all_are_super_seeding = true;
-        var all_are_auto_tmm = true;
+        let all_are_auto_tmm = true;
-        var there_are_auto_tmm = false;
+        let there_are_auto_tmm = false;
        const tagsSelectionState = Object.clone(tagList);
-        var h = torrentsTable.selectedRowsIds();
+        const h = torrentsTable.selectedRowsIds();
        h.each(function(item, index) {
-            var data = torrentsTable.rows.get(item).full_data;
+            const data = torrentsTable.rows.get(item).full_data;
            if (data['seq_dl'] !== true)
                all_are_seq_dl = false;
@ -342,12 +342,12 @@ var TorrentsTableContextMenu = new Class({
            }
        });
-        var show_seq_dl = true;
+        let show_seq_dl = true;
        if (!all_are_seq_dl && there_are_seq_dl)
            show_seq_dl = false;
-        var show_f_l_piece_prio = true;
+        let show_f_l_piece_prio = true;
        if (!all_are_f_l_piece_prio && there_are_f_l_piece_prio)
            show_f_l_piece_prio = false;
@ -412,7 +412,7 @@ var TorrentsTableContextMenu = new Class({
    },
    updateCategoriesSubMenu: function(category_list) {
-        var categoryList = $('contextCategoryList');
+        const categoryList = $('contextCategoryList');
        categoryList.empty();
        categoryList.appendChild(new Element('li', {
            html: '<a href="javascript:torrentNewCategoryFN();"><img src="images/qbt-theme/list-add.svg" alt="QBT_TR(New...)QBT_TR[CONTEXT=TransferListWidget]"/> QBT_TR(New...)QBT_TR[CONTEXT=TransferListWidget]</a>'
@ -421,16 +421,16 @@ var TorrentsTableContextMenu = new Class({
            html: '<a href="javascript:torrentSetCategoryFN(0);"><img src="images/qbt-theme/edit-clear.svg" alt="QBT_TR(Reset)QBT_TR[CONTEXT=TransferListWidget]"/> QBT_TR(Reset)QBT_TR[CONTEXT=TransferListWidget]</a>'
        }));
-        var sortedCategories = [];
+        const sortedCategories = [];
        Object.each(category_list, function(category) {
            sortedCategories.push(category.name);
        });
        sortedCategories.sort();
-        var first = true;
+        let first = true;
        Object.each(sortedCategories, function(categoryName) {
-            var categoryHash = genHash(categoryName);
+            const categoryHash = genHash(categoryName);
-            var el = new Element('li', {
+            const el = new Element('li', {
                html: '<a href="javascript:torrentSetCategoryFN(\'' + categoryHash + '\');"><img src="images/qbt-theme/inode-directory.svg"/> ' + escapeHtml(categoryName) + '</a>'
            });
            if (first) {
@ -479,10 +479,10 @@ var TorrentsTableContextMenu = new Class({
    }
 });
-var CategoriesFilterContextMenu = new Class({
+const CategoriesFilterContextMenu = new Class({
    Extends: ContextMenu,
    updateMenuItems: function() {
-        var id = this.options.element.id;
+        const id = this.options.element.id;
        if ((id != CATEGORIES_ALL) && (id != CATEGORIES_UNCATEGORIZED)) {
            this.showItem('editCategory');
            this.showItem('deleteCategory');
@ -505,13 +505,13 @@ const TagsFilterContextMenu = new Class({
    }
 });
-var SearchPluginsTableContextMenu = new Class({
+const SearchPluginsTableContextMenu = new Class({
    Extends: ContextMenu,
    updateMenuItems: function() {
-        var enabledColumnIndex = function(text) {
+        const enabledColumnIndex = function(text) {
-            var columns = $("searchPluginsTableFixedHeaderRow").getChildren("th");
+            const columns = $("searchPluginsTableFixedHeaderRow").getChildren("th");
-            for (var i = 0; i < columns.length; ++i)
+            for (let i = 0; i < columns.length; ++i)
                if (columns[i].get("html") === "Enabled")
                    return i;
        };
--- a/src/webui/www/private/scripts/download.js
+++ b/src/webui/www/private/scripts/download.js
@ -23,10 +23,10 @@
 'use strict';
-var categories = {};
+let categories = {};
-var defaultSavePath = "";
+let defaultSavePath = "";
-var getCategories = function() {
+const getCategories = function() {
    new Request.JSON({
        url: 'api/v2/torrents/categories',
        noCache: true,
@ -34,9 +34,9 @@ var getCategories = function() {
        onSuccess: function(data) {
            if (data) {
                categories = data;
-                for (var i in data) {
+                for (const i in data) {
-                    var category = data[i];
+                    const category = data[i];
-                    var option = new Element("option");
+                    const option = new Element("option");
                    option.set('value', category.name);
                    option.set('html', category.name);
                    $('categorySelect').appendChild(option);
@ -46,7 +46,7 @@ var getCategories = function() {
    }).send();
 };
-var getPreferences = function() {
+const getPreferences = function() {
    new Request.JSON({
        url: 'api/v2/app/preferences',
        method: 'get',
@ -74,7 +74,7 @@ var getPreferences = function() {
    }).send();
 };
-var changeCategorySelect = function(item) {
+const changeCategorySelect = function(item) {
    if (item.value == "\\other") {
        item.nextElementSibling.hidden = false;
        item.nextElementSibling.value = "";
@ -85,13 +85,13 @@ var changeCategorySelect = function(item) {
    }
    else {
        item.nextElementSibling.hidden = true;
-        var text = item.options[item.selectedIndex].innerHTML;
+        const text = item.options[item.selectedIndex].innerHTML;
        item.nextElementSibling.value = text;
        if ($('autoTMM').selectedIndex == 1) {
-            var categoryName = item.value;
+            const categoryName = item.value;
-            var category = categories[categoryName];
+            const category = categories[categoryName];
-            var savePath = defaultSavePath;
+            let savePath = defaultSavePath;
            if (category !== undefined)
                savePath = (category['savePath'] !== "") ? category['savePath'] : (defaultSavePath + categoryName);
            $('savepath').value = savePath;
@ -99,13 +99,13 @@ var changeCategorySelect = function(item) {
    }
 };
-var changeTMM = function(item) {
+const changeTMM = function(item) {
    if (item.selectedIndex == 1) {
        $('savepath').disabled = true;
-        var categorySelect = $('categorySelect');
+        const categorySelect = $('categorySelect');
-        var categoryName = categorySelect.options[categorySelect.selectedIndex].value;
+        const categoryName = categorySelect.options[categorySelect.selectedIndex].value;
-        var category = categories[categoryName];
+        const category = categories[categoryName];
        $('savepath').value = (category === undefined) ? "" : category['savePath'];
    }
    else {
--- a/src/webui/www/private/scripts/dynamicTable.js
+++ b/src/webui/www/private/scripts/dynamicTable.js
--- a/src/webui/www/private/scripts/misc.js
+++ b/src/webui/www/private/scripts/misc.js
@ -32,7 +32,7 @@
 * JS counterpart of the function in src/misc.cpp
 */
 function friendlyUnit(value, isSpeed) {
-    var units = [
+    const units = [
        "QBT_TR(B)QBT_TR[CONTEXT=misc]",
        "QBT_TR(KiB)QBT_TR[CONTEXT=misc]",
        "QBT_TR(MiB)QBT_TR[CONTEXT=misc]",
@ -45,7 +45,7 @@ function friendlyUnit(value, isSpeed) {
    if ((value === undefined) || (value === null) || (value < 0))
        return "QBT_TR(Unknown)QBT_TR[CONTEXT=misc]";
-    var i = 0;
+    let i = 0;
    while (value >= 1024.0 && i < 6) {
        value /= 1024.0;
        ++i;
@ -57,12 +57,12 @@ function friendlyUnit(value, isSpeed) {
        else return 3; // TiB, PiB, EiB
    }
-    var ret;
+    let ret;
    if (i === 0)
        ret = value + " " + units[i];
    else {
-        var precision = friendlyUnitPrecision(i);
+        const precision = friendlyUnitPrecision(i);
-        var offset = Math.pow(10, precision);
+        const offset = Math.pow(10, precision);
        // Don't round up
        ret = (Math.floor(offset * value) / offset).toFixed(precision) + " " + units[i];
    }
@ -76,21 +76,21 @@ function friendlyUnit(value, isSpeed) {
 * JS counterpart of the function in src/misc.cpp
 */
 function friendlyDuration(seconds) {
-    var MAX_ETA = 8640000;
+    const MAX_ETA = 8640000;
    if (seconds < 0 || seconds >= MAX_ETA)
        return "∞";
    if (seconds === 0)
        return "0";
    if (seconds < 60)
        return "QBT_TR(< 1m)QBT_TR[CONTEXT=misc]";
-    var minutes = seconds / 60;
+    let minutes = seconds / 60;
    if (minutes < 60)
        return "QBT_TR(%1m)QBT_TR[CONTEXT=misc]".replace("%1", parseInt(minutes));
-    var hours = minutes / 60;
+    let hours = minutes / 60;
    minutes = minutes % 60;
    if (hours < 24)
        return "QBT_TR(%1h %2m)QBT_TR[CONTEXT=misc]".replace("%1", parseInt(hours)).replace("%2", parseInt(minutes));
-    var days = hours / 24;
+    const days = hours / 24;
    hours = hours % 24;
    if (days < 100)
        return "QBT_TR(%1d %2h)QBT_TR[CONTEXT=misc]".replace("%1", parseInt(days)).replace("%2", parseInt(hours));
@ -98,7 +98,7 @@ function friendlyDuration(seconds) {
 }
 function friendlyPercentage(value) {
-    var percentage = (value * 100).round(1);
+    let percentage = (value * 100).round(1);
    if (isNaN(percentage) || (percentage < 0))
        percentage = 0;
    if (percentage > 100)
@ -141,12 +141,12 @@ if (!Date.prototype.toISOString) {
 * JS counterpart of the function in src/misc.cpp
 */
 function parseHtmlLinks(text) {
-    var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
+    const exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;
    return text.replace(exp, "<a target='_blank' href='$1'>$1</a>");
 }
 function escapeHtml(str) {
-    var div = document.createElement('div');
+    const div = document.createElement('div');
    div.appendChild(document.createTextNode(str));
    return div.innerHTML;
 }
--- a/src/webui/www/private/scripts/mocha-init.js
+++ b/src/webui/www/private/scripts/mocha-init.js
@ -53,43 +53,43 @@ if (typeof localStorage == 'undefined') {
 }
 function getLocalStorageItem(name, defaultVal) {
-    var val = localStorage.getItem(name);
+    let val = localStorage.getItem(name);
    if (val === null || val === undefined)
        val = defaultVal;
    return val;
 }
-var saveWindowSize = function() {};
+let saveWindowSize = function() {};
-var loadWindowWidth = function() {};
+let loadWindowWidth = function() {};
-var loadWindowHeight = function() {};
+let loadWindowHeight = function() {};
-var showDownloadPage = function() {};
+let showDownloadPage = function() {};
-var globalUploadLimitFN = function() {};
+let globalUploadLimitFN = function() {};
-var uploadLimitFN = function() {};
+let uploadLimitFN = function() {};
-var shareRatioFN = function() {};
+let shareRatioFN = function() {};
-var toggleSequentialDownloadFN = function() {};
+let toggleSequentialDownloadFN = function() {};
-var toggleFirstLastPiecePrioFN = function() {};
+let toggleFirstLastPiecePrioFN = function() {};
-var setSuperSeedingFN = function() {};
+let setSuperSeedingFN = function() {};
-var setForceStartFN = function() {};
+let setForceStartFN = function() {};
-var globalDownloadLimitFN = function() {};
+let globalDownloadLimitFN = function() {};
-var StatisticsLinkFN = function() {};
+let StatisticsLinkFN = function() {};
-var downloadLimitFN = function() {};
+let downloadLimitFN = function() {};
-var deleteFN = function() {};
+let deleteFN = function() {};
-var pauseFN = function() {};
+let pauseFN = function() {};
-var startFN = function() {};
+let startFN = function() {};
-var autoTorrentManagementFN = function() {};
+let autoTorrentManagementFN = function() {};
-var recheckFN = function() {};
+let recheckFN = function() {};
-var reannounceFN = function() {};
+let reannounceFN = function() {};
-var setLocationFN = function() {};
+let setLocationFN = function() {};
-var renameFN = function() {};
+let renameFN = function() {};
-var torrentNewCategoryFN = function() {};
+let torrentNewCategoryFN = function() {};
-var torrentSetCategoryFN = function() {};
+let torrentSetCategoryFN = function() {};
-var createCategoryFN = function() {};
+let createCategoryFN = function() {};
-var editCategoryFN = function() {};
+let editCategoryFN = function() {};
-var removeCategoryFN = function() {};
+let removeCategoryFN = function() {};
-var deleteUnusedCategoriesFN = function() {};
+let deleteUnusedCategoriesFN = function() {};
-var startTorrentsByCategoryFN = function() {};
+let startTorrentsByCategoryFN = function() {};
-var pauseTorrentsByCategoryFN = function() {};
+let pauseTorrentsByCategoryFN = function() {};
-var deleteTorrentsByCategoryFN = function() {};
+let deleteTorrentsByCategoryFN = function() {};
 let torrentAddTagsFN = function() {};
 let torrentSetTagsFN = function() {};
 let torrentRemoveAllTagsFN = function() {};
@ -99,14 +99,14 @@ let deleteUnusedTagsFN = function() {};
 let startTorrentsByTagFN = function() {};
 let pauseTorrentsByTagFN = function() {};
 let deleteTorrentsByTagFN = function() {};
-var copyNameFN = function() {};
+let copyNameFN = function() {};
-var copyMagnetLinkFN = function() {};
+let copyMagnetLinkFN = function() {};
-var copyHashFN = function() {};
+let copyHashFN = function() {};
-var setQueuePositionFN = function() {};
+let setQueuePositionFN = function() {};
-var initializeWindows = function() {
+const initializeWindows = function() {
    saveWindowSize = function(windowId) {
-        var size = $(windowId).getSize();
+        const size = $(windowId).getSize();
        localStorage.setItem('window_' + windowId + '_width', size.x);
        localStorage.setItem('window_' + windowId + '_height', size.y);
    };
@ -133,8 +133,8 @@ var initializeWindows = function() {
    });
    showDownloadPage = function(urls) {
-        var id = 'downloadPage';
+        const id = 'downloadPage';
-        var contentUrl = 'download.html';
+        let contentUrl = 'download.html';
        if (urls && urls.length)
            contentUrl += '?urls=' + urls.join("|");
@ -160,7 +160,7 @@ var initializeWindows = function() {
    addClickEvent('preferences', function(e) {
        new Event(e).stop();
-        var id = 'preferencesPage';
+        const id = 'preferencesPage';
        new MochaUI.Window({
            id: id,
            title: "QBT_TR(Options)QBT_TR[CONTEXT=OptionsDialog]",
@ -185,7 +185,7 @@ var initializeWindows = function() {
    addClickEvent('upload', function(e) {
        new Event(e).stop();
-        var id = 'uploadPage';
+        const id = 'uploadPage';
        new MochaUI.Window({
            id: id,
            title: "QBT_TR(Upload local torrent)QBT_TR[CONTEXT=HttpServer]",
@ -222,7 +222,7 @@ var initializeWindows = function() {
    };
    uploadLimitFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new MochaUI.Window({
                id: 'uploadLimitPage',
@ -241,16 +241,16 @@ var initializeWindows = function() {
    };
    shareRatioFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
-            var shareRatio = null;
+            let shareRatio = null;
-            var torrentsHaveSameShareRatio = true;
+            let torrentsHaveSameShareRatio = true;
            // check if all selected torrents have same share ratio
-            for (var i = 0; i < hashes.length; ++i) {
+            for (let i = 0; i < hashes.length; ++i) {
-                var hash = hashes[i];
+                const hash = hashes[i];
-                var row = torrentsTable.rows[hash].full_data;
+                const row = torrentsTable.rows[hash].full_data;
-                var origValues = row.ratio_limit + "|" + row.seeding_time_limit + "|" + row.max_ratio + "|" + row.max_seeding_time;
+                const origValues = row.ratio_limit + "|" + row.seeding_time_limit + "|" + row.max_ratio + "|" + row.max_seeding_time;
                // initialize value
                if (shareRatio === null)
@ -263,7 +263,7 @@ var initializeWindows = function() {
            }
            // if all torrents have same share ratio, display that share ratio. else use the default
-            var orig = torrentsHaveSameShareRatio ? shareRatio : "";
+            const orig = torrentsHaveSameShareRatio ? shareRatio : "";
            new MochaUI.Window({
                id: 'shareRatioPage',
                title: "QBT_TR(Torrent Upload/Download Ratio Limiting)QBT_TR[CONTEXT=UpDownRatioDialog]",
@ -280,7 +280,7 @@ var initializeWindows = function() {
    };
    toggleSequentialDownloadFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/toggleSequentialDownload',
@ -294,7 +294,7 @@ var initializeWindows = function() {
    };
    toggleFirstLastPiecePrioFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/toggleFirstLastPiecePrio',
@ -308,7 +308,7 @@ var initializeWindows = function() {
    };
    setSuperSeedingFN = function(val) {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/setSuperSeeding',
@ -323,7 +323,7 @@ var initializeWindows = function() {
    };
    setForceStartFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/setForceStart',
@ -354,7 +354,7 @@ var initializeWindows = function() {
    };
    StatisticsLinkFN = function() {
-        var id = 'statisticspage';
+        const id = 'statisticspage';
        new MochaUI.Window({
            id: id,
            title: 'QBT_TR(Statistics)QBT_TR[CONTEXT=StatsDialog]',
@ -371,7 +371,7 @@ var initializeWindows = function() {
    };
    downloadLimitFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new MochaUI.Window({
                id: 'downloadLimitPage',
@ -390,7 +390,7 @@ var initializeWindows = function() {
    };
    deleteFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new MochaUI.Window({
                id: 'confirmDeletionPage',
@ -414,7 +414,7 @@ var initializeWindows = function() {
    });
    pauseFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/pause',
@ -428,7 +428,7 @@ var initializeWindows = function() {
    };
    startFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/resume',
@ -442,11 +442,11 @@ var initializeWindows = function() {
    };
    autoTorrentManagementFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
-            var enable = false;
+            let enable = false;
            hashes.each(function(hash, index) {
-                var row = torrentsTable.rows[hash];
+                const row = torrentsTable.rows[hash];
                if (!row.full_data.auto_tmm)
                    enable = true;
            });
@ -463,7 +463,7 @@ var initializeWindows = function() {
    };
    recheckFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/recheck',
@ -477,7 +477,7 @@ var initializeWindows = function() {
    };
    reannounceFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/reannounce',
@ -491,11 +491,11 @@ var initializeWindows = function() {
    };
    setLocationFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
-            var hash = hashes[0];
+            const hash = hashes[0];
-            var row = torrentsTable.rows[hash];
+            const row = torrentsTable.rows[hash];
-            var path = encodeURIComponent(row.full_data.save_path);
+            const path = encodeURIComponent(row.full_data.save_path);
            new MochaUI.Window({
                id: 'setLocationPage',
                title: "QBT_TR(Set location)QBT_TR[CONTEXT=TransferListWidget]",
@ -513,10 +513,10 @@ var initializeWindows = function() {
    };
    renameFN = function() {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length == 1) {
-            var hash = hashes[0];
+            const hash = hashes[0];
-            var row = torrentsTable.rows[hash];
+            const row = torrentsTable.rows[hash];
            if (row) {
                new MochaUI.Window({
                    id: 'renamePage',
@ -536,8 +536,8 @@ var initializeWindows = function() {
    };
    torrentNewCategoryFN = function() {
-        var action = "set";
+        const action = "set";
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new MochaUI.Window({
                id: 'newCategoryPage',
@ -556,10 +556,10 @@ var initializeWindows = function() {
    };
    torrentSetCategoryFN = function(categoryHash) {
-        var categoryName = '';
+        let categoryName = '';
        if (categoryHash != 0)
            categoryName = category_list[categoryHash].name;
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/setCategory',
@ -573,7 +573,7 @@ var initializeWindows = function() {
    };
    createCategoryFN = function() {
-        var action = "create";
+        const action = "create";
        new MochaUI.Window({
            id: 'newCategoryPage',
            title: "QBT_TR(New Category)QBT_TR[CONTEXT=CategoryFilterWidget]",
@ -591,9 +591,9 @@ var initializeWindows = function() {
    };
    editCategoryFN = function(categoryHash) {
-        var action = "edit";
+        const action = "edit";
-        var categoryName = category_list[categoryHash].name;
+        const categoryName = category_list[categoryHash].name;
-        var savePath = category_list[categoryHash].savePath;
+        const savePath = category_list[categoryHash].savePath;
        new MochaUI.Window({
            id: 'editCategoryPage',
            title: "QBT_TR(Edit Category)QBT_TR[CONTEXT=TransferListWidget]",
@ -611,7 +611,7 @@ var initializeWindows = function() {
    };
    removeCategoryFN = function(categoryHash) {
-        var categoryName = category_list[categoryHash].name;
+        const categoryName = category_list[categoryHash].name;
        new Request({
            url: 'api/v2/torrents/removeCategories',
            method: 'post',
@ -623,8 +623,8 @@ var initializeWindows = function() {
    };
    deleteUnusedCategoriesFN = function() {
-        var categories = [];
+        const categories = [];
-        for (var hash in category_list) {
+        for (const hash in category_list) {
            if (torrentsTable.getFilteredTorrentsNumber('all', hash, TAGS_ALL) === 0)
                categories.push(category_list[hash].name);
        }
@ -639,7 +639,7 @@ var initializeWindows = function() {
    };
    startTorrentsByCategoryFN = function(categoryHash) {
-        var hashes = torrentsTable.getFilteredTorrentsHashes('all', categoryHash, TAGS_ALL);
+        const hashes = torrentsTable.getFilteredTorrentsHashes('all', categoryHash, TAGS_ALL);
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/resume',
@ -653,7 +653,7 @@ var initializeWindows = function() {
    };
    pauseTorrentsByCategoryFN = function(categoryHash) {
-        var hashes = torrentsTable.getFilteredTorrentsHashes('all', categoryHash, TAGS_ALL);
+        const hashes = torrentsTable.getFilteredTorrentsHashes('all', categoryHash, TAGS_ALL);
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/pause',
@ -667,7 +667,7 @@ var initializeWindows = function() {
    };
    deleteTorrentsByCategoryFN = function(categoryHash) {
-        var hashes = torrentsTable.getFilteredTorrentsHashes('all', categoryHash, TAGS_ALL);
+        const hashes = torrentsTable.getFilteredTorrentsHashes('all', categoryHash, TAGS_ALL);
        if (hashes.length) {
            new MochaUI.Window({
                id: 'confirmDeletionPage',
@ -827,12 +827,12 @@ var initializeWindows = function() {
    };
    copyNameFN = function() {
-        var selectedRows = torrentsTable.selectedRowsIds();
+        const selectedRows = torrentsTable.selectedRowsIds();
-        var names = [];
+        const names = [];
        if (selectedRows.length) {
-            var rows = torrentsTable.getFilteredAndSortedRows();
+            const rows = torrentsTable.getFilteredAndSortedRows();
-            for (var i = 0; i < selectedRows.length; ++i) {
+            for (let i = 0; i < selectedRows.length; ++i) {
-                var hash = selectedRows[i];
+                const hash = selectedRows[i];
                names.push(rows[hash].full_data.name);
            }
        }
@ -840,12 +840,12 @@ var initializeWindows = function() {
    };
    copyMagnetLinkFN = function() {
-        var selectedRows = torrentsTable.selectedRowsIds();
+        const selectedRows = torrentsTable.selectedRowsIds();
-        var magnets = [];
+        const magnets = [];
        if (selectedRows.length) {
-            var rows = torrentsTable.getFilteredAndSortedRows();
+            const rows = torrentsTable.getFilteredAndSortedRows();
-            for (var i = 0; i < selectedRows.length; ++i) {
+            for (let i = 0; i < selectedRows.length; ++i) {
-                var hash = selectedRows[i];
+                const hash = selectedRows[i];
                magnets.push(rows[hash].full_data.magnet_uri);
            }
        }
@ -873,7 +873,7 @@ var initializeWindows = function() {
    ['pause', 'resume', 'recheck'].each(function(item) {
        addClickEvent(item, function(e) {
            new Event(e).stop();
-            var hashes = torrentsTable.selectedRowsIds();
+            const hashes = torrentsTable.selectedRowsIds();
            if (hashes.length) {
                hashes.each(function(hash, index) {
                    new Request({
@ -897,7 +897,7 @@ var initializeWindows = function() {
    });
    setQueuePositionFN = function(cmd) {
-        var hashes = torrentsTable.selectedRowsIds();
+        const hashes = torrentsTable.selectedRowsIds();
        if (hashes.length) {
            new Request({
                url: 'api/v2/torrents/' + cmd,
@ -912,7 +912,7 @@ var initializeWindows = function() {
    addClickEvent('about', function(e) {
        new Event(e).stop();
-        var id = 'aboutpage';
+        const id = 'aboutpage';
        new MochaUI.Window({
            id: id,
            title: 'QBT_TR(About qBittorrent)QBT_TR[CONTEXT=AboutDialog]',
--- a/src/webui/www/private/scripts/progressbar.js
+++ b/src/webui/www/private/scripts/progressbar.js
@ -28,9 +28,9 @@
 'use strict';
-var ProgressBar = new Class({
+const ProgressBar = new Class({
    initialize: function(value, parameters) {
-        var vals = {
+        const vals = {
            'id': 'progressbar_' + (ProgressBars++),
            'value': $pick(value, 0),
            'width': 0,
@ -42,7 +42,7 @@ var ProgressBar = new Class({
        };
        if (parameters && $type(parameters) == 'object') $extend(vals, parameters);
        if (vals.height < 12) vals.height = 12;
-        var obj = new Element('div', {
+        const obj = new Element('div', {
            'id': vals.id,
            'class': 'progressbar_wrapper',
            'styles': {
@ -110,7 +110,7 @@ function ProgressBar_setValue(value) {
    this.vals.light.empty();
    this.vals.dark.appendText(value.round(1).toFixed(1) + '%');
    this.vals.light.appendText(value.round(1).toFixed(1) + '%');
-    var r = parseInt(this.vals.width * (value / 100));
+    const r = parseInt(this.vals.width * (value / 100));
    this.vals.dark.setStyle('clip', 'rect(0,' + r + 'px,' + this.vals.height + 'px,0)');
    this.vals.light.setStyle('clip', 'rect(0,' + this.vals.width + 'px,' + this.vals.height + 'px,' + r + 'px)');
 }
@ -126,15 +126,15 @@ function ProgressBar_setWidth(value) {
 }
 function ProgressBar_checkForParent(id) {
-    var obj = $(id);
+    const obj = $(id);
    if (!obj) return;
    if (!obj.parentNode) return setTimeout('ProgressBar_checkForParent("' + id + '")', 1);
    obj.setStyle('width', '100%');
-    var w = obj.offsetWidth;
+    const w = obj.offsetWidth;
    obj.vals.dark.setStyle('width', w);
    obj.vals.light.setStyle('width', w);
    obj.vals.width = w;
    obj.setValue(obj.vals.value);
 }
-var ProgressBars = 0;
+let ProgressBars = 0;
--- a/src/webui/www/private/scripts/prop-files.js
+++ b/src/webui/www/private/scripts/prop-files.js
@ -28,10 +28,10 @@
 'use strict';
-var is_seed = true;
+let is_seed = true;
-var current_hash = "";
+this.current_hash = "";
-var FilePriority = {
+const FilePriority = {
    "Ignored": 0,
    "Normal": 1,
    "High": 6,
@ -39,7 +39,7 @@ var FilePriority = {
    "Mixed": -1
 };
-var normalizePriority = function(priority) {
+const normalizePriority = function(priority) {
    switch (priority) {
        case FilePriority.Ignored:
        case FilePriority.Normal:
@ -52,30 +52,30 @@ var normalizePriority = function(priority) {
    }
 };
-var fileCheckboxChanged = function(e) {
+const fileCheckboxChanged = function(e) {
-    var checkbox = e.target;
+    const checkbox = e.target;
-    var priority = checkbox.checked ? FilePriority.Normal : FilePriority.Ignored;
+    const priority = checkbox.checked ? FilePriority.Normal : FilePriority.Ignored;
-    var id = checkbox.get('data-id');
+    const id = checkbox.get('data-id');
    setFilePriority(id, priority);
    setGlobalCheckboxState();
    return true;
 };
-var fileComboboxChanged = function(e) {
+const fileComboboxChanged = function(e) {
-    var combobox = e.target;
+    const combobox = e.target;
-    var newPriority = combobox.value;
+    const newPriority = combobox.value;
-    var id = combobox.get('data-id');
+    const id = combobox.get('data-id');
    setFilePriority(id, newPriority);
 };
-var isDownloadCheckboxExists = function(id) {
+const isDownloadCheckboxExists = function(id) {
    return ($('cbPrio' + id) !== null);
 };
-var createDownloadCheckbox = function(id, download) {
+const createDownloadCheckbox = function(id, download) {
-    var checkbox = new Element('input');
+    const checkbox = new Element('input');
    checkbox.set('type', 'checkbox');
    if (download)
        checkbox.set('checked', 'checked');
@ -86,17 +86,17 @@ var createDownloadCheckbox = function(id, download) {
    return checkbox;
 };
-var updateDownloadCheckbox = function(id, download) {
+const updateDownloadCheckbox = function(id, download) {
-    var checkbox = $('cbPrio' + id);
+    const checkbox = $('cbPrio' + id);
    checkbox.checked = download;
 };
-var isPriorityComboExists = function(id) {
+const isPriorityComboExists = function(id) {
    return ($('comboPrio' + id) !== null);
 };
-var createPriorityOptionElement = function(priority, selected, html) {
+const createPriorityOptionElement = function(priority, selected, html) {
-    var elem = new Element('option');
+    const elem = new Element('option');
    elem.set('value', priority.toString());
    elem.set('html', html);
    if (selected)
@ -104,8 +104,8 @@ var createPriorityOptionElement = function(priority, selected, html) {
    return elem;
 };
-var createPriorityCombo = function(id, selectedPriority) {
+const createPriorityCombo = function(id, selectedPriority) {
-    var select = new Element('select');
+    const select = new Element('select');
    select.set('id', 'comboPrio' + id);
    select.set('data-id', id);
    select.set('disabled', is_seed);
@ -120,8 +120,8 @@ var createPriorityCombo = function(id, selectedPriority) {
    return select;
 };
-var updatePriorityCombo = function(id, selectedPriority) {
+const updatePriorityCombo = function(id, selectedPriority) {
-    var combobox = $('comboPrio' + id);
+    const combobox = $('comboPrio' + id);
    if (parseInt(combobox.value) !== selectedPriority)
        selectComboboxPriority(combobox, selectedPriority);
@ -130,10 +130,10 @@ var updatePriorityCombo = function(id, selectedPriority) {
        combobox.disabled = is_seed;
 };
-var selectComboboxPriority = function(combobox, priority) {
+const selectComboboxPriority = function(combobox, priority) {
-    var options = combobox.options;
+    const options = combobox.options;
-    for (var i = 0; i < options.length; ++i) {
+    for (let i = 0; i < options.length; ++i) {
-        var option = options[i];
+        const option = options[i];
        if (parseInt(option.value) === priority)
            option.setAttribute('selected', '');
        else
@ -143,9 +143,9 @@ var selectComboboxPriority = function(combobox, priority) {
    combobox.value = priority;
 };
-var switchCheckboxState = function() {
+const switchCheckboxState = function() {
-    var rows = [];
+    const rows = [];
-    var priority = FilePriority.Ignored;
+    let priority = FilePriority.Ignored;
    if ($('tristate_cb').state === "checked") {
        setGlobalCheckboxUnchecked();
@ -169,7 +169,7 @@ var switchCheckboxState = function() {
        setFilePriority(rows, priority);
 };
-var setGlobalCheckboxState = function() {
+const setGlobalCheckboxState = function() {
    if (isAllCheckboxesChecked())
        setGlobalCheckboxChecked();
    else if (isAllCheckboxesUnchecked())
@ -178,44 +178,44 @@ var setGlobalCheckboxState = function() {
        setGlobalCheckboxPartial();
 };
-var setGlobalCheckboxChecked = function() {
+const setGlobalCheckboxChecked = function() {
    $('tristate_cb').state = "checked";
    $('tristate_cb').indeterminate = false;
    $('tristate_cb').checked = true;
 };
-var setGlobalCheckboxUnchecked = function() {
+const setGlobalCheckboxUnchecked = function() {
    $('tristate_cb').state = "unchecked";
    $('tristate_cb').indeterminate = false;
    $('tristate_cb').checked = false;
 };
-var setGlobalCheckboxPartial = function() {
+const setGlobalCheckboxPartial = function() {
    $('tristate_cb').state = "partial";
    $('tristate_cb').indeterminate = true;
 };
-var isAllCheckboxesChecked = function() {
+const isAllCheckboxesChecked = function() {
-    var checkboxes = $$('input.DownloadedCB');
+    const checkboxes = $$('input.DownloadedCB');
-    for (var i = 0; i < checkboxes.length; ++i) {
+    for (let i = 0; i < checkboxes.length; ++i) {
        if (!checkboxes[i].checked)
            return false;
    }
    return true;
 };
-var isAllCheckboxesUnchecked = function() {
+const isAllCheckboxesUnchecked = function() {
-    var checkboxes = $$('input.DownloadedCB');
+    const checkboxes = $$('input.DownloadedCB');
-    for (var i = 0; i < checkboxes.length; ++i) {
+    for (let i = 0; i < checkboxes.length; ++i) {
        if (checkboxes[i].checked)
            return false;
    }
    return true;
 };
-var setFilePriority = function(id, priority) {
+const setFilePriority = function(id, priority) {
    if (current_hash === "") return;
-    var ids = Array.isArray(id) ? id : [id];
+    const ids = Array.isArray(id) ? id : [id];
    clearTimeout(loadTorrentFilesDataTimer);
    new Request({
@ -232,20 +232,20 @@ var setFilePriority = function(id, priority) {
    }).send();
    ids.forEach(function(_id) {
-        var combobox = $('comboPrio' + _id);
+        const combobox = $('comboPrio' + _id);
        if (combobox !== null)
            selectComboboxPriority(combobox, priority);
    });
 };
-var loadTorrentFilesDataTimer;
+let loadTorrentFilesDataTimer;
-var loadTorrentFilesData = function() {
+const loadTorrentFilesData = function() {
    if ($('prop_files').hasClass('invisible')
        || $('propertiesPanel_collapseToggle').hasClass('panel-expand')) {
        // Tab changed, don't do anything
        return;
    }
-    var new_hash = torrentsTable.getCurrentTorrentHash();
+    const new_hash = torrentsTable.getCurrentTorrentHash();
    if (new_hash === "") {
        torrentFilesTable.clear();
        clearTimeout(loadTorrentFilesDataTimer);
@ -256,7 +256,7 @@ var loadTorrentFilesData = function() {
        torrentFilesTable.clear();
        current_hash = new_hash;
    }
-    var url = new URI('api/v2/torrents/files?hash=' + current_hash);
+    const url = new URI('api/v2/torrents/files?hash=' + current_hash);
    new Request.JSON({
        url: url,
        noCache: true,
@ -266,19 +266,19 @@ var loadTorrentFilesData = function() {
            loadTorrentFilesDataTimer = loadTorrentFilesData.delay(5000);
        },
        onSuccess: function(files) {
-            var selectedFiles = torrentFilesTable.selectedRowsIds();
+            const selectedFiles = torrentFilesTable.selectedRowsIds();
            if (!files) {
                torrentFilesTable.clear();
                return;
            }
-            var i = 0;
+            let i = 0;
            files.each(function(file) {
                if (i === 0)
                    is_seed = file.is_seed;
-                var row = {
+                const row = {
                    rowId: i,
                    checked: (file.priority !== FilePriority.Ignored),
                    name: escapeHtml(file.name),
@ -307,35 +307,35 @@ var loadTorrentFilesData = function() {
    }).send();
 };
-var updateTorrentFilesData = function() {
+updateTorrentFilesData = function() {
    clearTimeout(loadTorrentFilesDataTimer);
    loadTorrentFilesData();
 };
-var torrentFilesContextMenu = new ContextMenu({
+const torrentFilesContextMenu = new ContextMenu({
    targets: '#torrentFilesTableDiv tr',
    menu: 'torrentFilesMenu',
    actions: {
        FilePrioIgnore: function(element, ref) {
-            var selectedRows = torrentFilesTable.selectedRowsIds();
+            const selectedRows = torrentFilesTable.selectedRowsIds();
            if (selectedRows.length === 0) return;
            setFilePriority(selectedRows, FilePriority.Ignored);
        },
        FilePrioNormal: function(element, ref) {
-            var selectedRows = torrentFilesTable.selectedRowsIds();
+            const selectedRows = torrentFilesTable.selectedRowsIds();
            if (selectedRows.length === 0) return;
            setFilePriority(selectedRows, FilePriority.Normal);
        },
        FilePrioHigh: function(element, ref) {
-            var selectedRows = torrentFilesTable.selectedRowsIds();
+            const selectedRows = torrentFilesTable.selectedRowsIds();
            if (selectedRows.length === 0) return;
            setFilePriority(selectedRows, FilePriority.High);
        },
        FilePrioMaximum: function(element, ref) {
-            var selectedRows = torrentFilesTable.selectedRowsIds();
+            const selectedRows = torrentFilesTable.selectedRowsIds();
            if (selectedRows.length === 0) return;
            setFilePriority(selectedRows, FilePriority.Maximum);
@ -357,14 +357,14 @@ var torrentFilesContextMenu = new ContextMenu({
 torrentFilesTable.setup('torrentFilesTableDiv', 'torrentFilesTableFixedHeaderDiv', torrentFilesContextMenu);
 // inject checkbox into table header
-var tableHeaders = $$('#torrentFilesTableFixedHeaderDiv .dynamicTableHeader th');
+const tableHeaders = $$('#torrentFilesTableFixedHeaderDiv .dynamicTableHeader th');
 if (tableHeaders.length > 0) {
-    var checkbox = new Element('input');
+    const checkbox = new Element('input');
    checkbox.set('type', 'checkbox');
    checkbox.set('id', 'tristate_cb');
    checkbox.addEvent('click', switchCheckboxState);
-    var checkboxTH = tableHeaders[0];
+    const checkboxTH = tableHeaders[0];
    checkbox.injectInside(checkboxTH);
 }
--- a/src/webui/www/private/scripts/prop-general.js
+++ b/src/webui/www/private/scripts/prop-general.js
@ -28,7 +28,7 @@
 'use strict';
-var clearData = function() {
+const clearData = function() {
    $('time_elapsed').set('html', '');
    $('eta').set('html', '');
    $('nb_connections').set('html', '');
@ -55,14 +55,14 @@ var clearData = function() {
    $('comment').set('html', '');
 };
-var loadTorrentDataTimer;
+let loadTorrentDataTimer;
-var loadTorrentData = function() {
+const loadTorrentData = function() {
    if ($('prop_general').hasClass('invisible')
        || $('propertiesPanel_collapseToggle').hasClass('panel-expand')) {
        // Tab changed, don't do anything
        return;
    }
-    var current_hash = torrentsTable.getCurrentTorrentHash();
+    const current_hash = torrentsTable.getCurrentTorrentHash();
    if (current_hash === "") {
        clearData();
        clearTimeout(loadTorrentDataTimer);
@ -71,7 +71,7 @@ var loadTorrentData = function() {
    }
    // Display hash
    $('torrent_hash').set('html', current_hash);
-    var url = new URI('api/v2/torrents/properties?hash=' + current_hash);
+    const url = new URI('api/v2/torrents/properties?hash=' + current_hash);
    new Request.JSON({
        url: url,
        noCache: true,
@ -84,7 +84,7 @@ var loadTorrentData = function() {
        onSuccess: function(data) {
            $('error_div').set('html', '');
            if (data) {
-                var temp;
+                let temp;
                // Update Torrent data
                if (data.seeding_time > 0)
                    temp = "QBT_TR(%1 (%2 this session))QBT_TR[CONTEXT=PropertiesWidget]"
@ -193,7 +193,7 @@ var loadTorrentData = function() {
    }).send();
 };
-var updateTorrentData = function() {
+updateTorrentData = function() {
    clearTimeout(loadTorrentDataTimer);
    loadTorrentData();
 };
--- a/src/webui/www/private/scripts/prop-peers.js
+++ b/src/webui/www/private/scripts/prop-peers.js
@ -28,17 +28,17 @@
 'use strict';
-var loadTorrentPeersTimer;
+let loadTorrentPeersTimer;
-var syncTorrentPeersLastResponseId = 0;
+let syncTorrentPeersLastResponseId = 0;
-var show_flags = true;
+let show_flags = true;
-var loadTorrentPeersData = function() {
+const loadTorrentPeersData = function() {
    if ($('prop_peers').hasClass('invisible')
        || $('propertiesPanel_collapseToggle').hasClass('panel-expand')) {
        syncTorrentPeersLastResponseId = 0;
        torrentPeersTable.clear();
        return;
    }
-    var current_hash = torrentsTable.getCurrentTorrentHash();
+    const current_hash = torrentsTable.getCurrentTorrentHash();
    if (current_hash === "") {
        syncTorrentPeersLastResponseId = 0;
        torrentPeersTable.clear();
@ -46,7 +46,7 @@ var loadTorrentPeersData = function() {
        loadTorrentPeersTimer = loadTorrentPeersData.delay(getSyncMainDataInterval());
        return;
    }
-    var url = new URI('api/v2/sync/torrentPeers');
+    const url = new URI('api/v2/sync/torrentPeers');
    url.setData('rid', syncTorrentPeersLastResponseId);
    url.setData('hash', current_hash);
    new Request.JSON({
@ -60,13 +60,13 @@ var loadTorrentPeersData = function() {
        onSuccess: function(response) {
            $('error_div').set('html', '');
            if (response) {
-                var full_update = (response['full_update'] === true);
+                const full_update = (response['full_update'] === true);
                if (full_update)
                    torrentPeersTable.clear();
                if (response['rid'])
                    syncTorrentPeersLastResponseId = response['rid'];
                if (response['peers']) {
-                    for (var key in response['peers']) {
+                    for (const key in response['peers']) {
                        response['peers'][key]['rowId'] = key;
                        if (response['peers'][key]['client'])
--- a/src/webui/www/private/scripts/prop-trackers.js
+++ b/src/webui/www/private/scripts/prop-trackers.js
@ -28,16 +28,16 @@
 'use strict';
-var current_hash = "";
+this.current_hash = "";
-var loadTrackersDataTimer;
+let loadTrackersDataTimer;
-var loadTrackersData = function() {
+const loadTrackersData = function() {
    if ($('prop_trackers').hasClass('invisible')
        || $('propertiesPanel_collapseToggle').hasClass('panel-expand')) {
        // Tab changed, don't do anything
        return;
    }
-    var new_hash = torrentsTable.getCurrentTorrentHash();
+    const new_hash = torrentsTable.getCurrentTorrentHash();
    if (new_hash === "") {
        torrentTrackersTable.clear();
        clearTimeout(loadTrackersDataTimer);
@ -48,7 +48,7 @@ var loadTrackersData = function() {
        torrentTrackersTable.clear();
        current_hash = new_hash;
    }
-    var url = new URI('api/v2/torrents/trackers?hash=' + current_hash);
+    const url = new URI('api/v2/torrents/trackers?hash=' + current_hash);
    new Request.JSON({
        url: url,
        noCache: true,
@ -58,13 +58,13 @@ var loadTrackersData = function() {
            loadTrackersDataTimer = loadTrackersData.delay(10000);
        },
        onSuccess: function(trackers) {
-            var selectedTrackers = torrentTrackersTable.selectedRowsIds();
+            const selectedTrackers = torrentTrackersTable.selectedRowsIds();
            torrentTrackersTable.clear();
            if (trackers) {
                trackers.each(function(tracker) {
-                    var url = escapeHtml(tracker.url);
+                    const url = escapeHtml(tracker.url);
-                    var status;
+                    let status;
                    switch (tracker.status) {
                        case 0:
                            status = "QBT_TR(Disabled)QBT_TR[CONTEXT=TrackerListWidget]";
@ -83,7 +83,7 @@ var loadTrackersData = function() {
                            break;
                    }
-                    var row = {
+                    const row = {
                        rowId: url,
                        tier: tracker.tier,
                        url: url,
@ -108,12 +108,12 @@ var loadTrackersData = function() {
    }).send();
 };
-var updateTrackersData = function() {
+updateTrackersData = function() {
    clearTimeout(loadTrackersDataTimer);
    loadTrackersData();
 };
-var torrentTrackersContextMenu = new ContextMenu({
+const torrentTrackersContextMenu = new ContextMenu({
    targets: '#torrentTrackersTableDiv',
    menu: 'torrentTrackersMenu',
    actions: {
@ -134,8 +134,8 @@ var torrentTrackersContextMenu = new ContextMenu({
        y: 2
    },
    onShow: function() {
-        var selectedTrackers = torrentTrackersTable.selectedRowsIds();
+        const selectedTrackers = torrentTrackersTable.selectedRowsIds();
-        var containsStaticTracker = selectedTrackers.some(function(tracker) {
+        const containsStaticTracker = selectedTrackers.some(function(tracker) {
            return (tracker.indexOf("** [") === 0);
        });
@ -152,7 +152,7 @@ var torrentTrackersContextMenu = new ContextMenu({
    }
 });
-var addTrackerFN = function() {
+const addTrackerFN = function() {
    if (current_hash.length === 0) return;
    new MochaUI.Window({
        id: 'trackersPage',
@ -173,10 +173,10 @@ var addTrackerFN = function() {
    });
 };
-var editTrackerFN = function(element) {
+const editTrackerFN = function(element) {
    if (current_hash.length === 0) return;
-    var trackerUrl = encodeURIComponent(element.childNodes[1].innerText);
+    const trackerUrl = encodeURIComponent(element.childNodes[1].innerText);
    new MochaUI.Window({
        id: 'trackersPage',
        title: "QBT_TR(Tracker editing)QBT_TR[CONTEXT=TrackerListWidget]",
@ -196,10 +196,10 @@ var editTrackerFN = function(element) {
    });
 };
-var removeTrackerFN = function(element) {
+const removeTrackerFN = function(element) {
    if (current_hash.length === 0) return;
-    var selectedTrackers = torrentTrackersTable.selectedRowsIds();
+    const selectedTrackers = torrentTrackersTable.selectedRowsIds();
    new Request({
        url: 'api/v2/torrents/removeTrackers',
        method: 'post',
--- a/src/webui/www/private/scripts/prop-webseeds.js
+++ b/src/webui/www/private/scripts/prop-webseeds.js
@ -28,7 +28,7 @@
 'use strict';
-var webseedsDynTable = new Class({
+const webseedsDynTable = new Class({
    initialize: function() {},
@ -39,7 +39,7 @@ var webseedsDynTable = new Class({
    removeRow: function(url) {
        if (this.rows.has(url)) {
-            var tr = this.rows.get(url);
+            const tr = this.rows.get(url);
            tr.dispose();
            this.rows.erase(url);
            return true;
@ -54,25 +54,25 @@ var webseedsDynTable = new Class({
    },
    updateRow: function(tr, row) {
-        var tds = tr.getElements('td');
+        const tds = tr.getElements('td');
-        for (var i = 0; i < row.length; ++i) {
+        for (let i = 0; i < row.length; ++i) {
            tds[i].set('html', row[i]);
        }
        return true;
    },
    insertRow: function(row) {
-        var url = row[0];
+        const url = row[0];
        if (this.rows.has(url)) {
-            var tableRow = this.rows.get(url);
+            const tableRow = this.rows.get(url);
            this.updateRow(tableRow, row);
            return;
        }
        //this.removeRow(id);
-        var tr = new Element('tr');
+        const tr = new Element('tr');
        this.rows.set(url, tr);
-        for (var i = 0; i < row.length; ++i) {
+        for (let i = 0; i < row.length; ++i) {
-            var td = new Element('td');
+            const td = new Element('td');
            td.set('html', row[i]);
            td.injectInside(tr);
        }
@ -80,16 +80,16 @@ var webseedsDynTable = new Class({
    },
 });
-var current_hash = "";
+this.current_hash = "";
-var loadWebSeedsDataTimer;
+let loadWebSeedsDataTimer;
-var loadWebSeedsData = function() {
+const loadWebSeedsData = function() {
    if ($('prop_webseeds').hasClass('invisible')
        || $('propertiesPanel_collapseToggle').hasClass('panel-expand')) {
        // Tab changed, don't do anything
        return;
    }
-    var new_hash = torrentsTable.getCurrentTorrentHash();
+    const new_hash = torrentsTable.getCurrentTorrentHash();
    if (new_hash === "") {
        wsTable.removeAllRows();
        clearTimeout(loadWebSeedsDataTimer);
@ -100,7 +100,7 @@ var loadWebSeedsData = function() {
        wsTable.removeAllRows();
        current_hash = new_hash;
    }
-    var url = new URI('api/v2/torrents/webseeds?hash=' + current_hash);
+    const url = new URI('api/v2/torrents/webseeds?hash=' + current_hash);
    new Request.JSON({
        url: url,
        noCache: true,
@ -115,7 +115,7 @@ var loadWebSeedsData = function() {
            if (webseeds) {
                // Update WebSeeds data
                webseeds.each(function(webseed) {
-                    var row = [];
+                    const row = [];
                    row.length = 1;
                    row[0] = webseed.url;
                    wsTable.insertRow(row);
@ -130,10 +130,10 @@ var loadWebSeedsData = function() {
    }).send();
 };
-var updateWebSeedsData = function() {
+updateWebSeedsData = function() {
    clearTimeout(loadWebSeedsDataTimer);
    loadWebSeedsData();
 };
-var wsTable = new webseedsDynTable();
+const wsTable = new webseedsDynTable();
 wsTable.setup($('webseedsTable'));
--- a/src/webui/www/private/scripts/speedslider.js
+++ b/src/webui/www/private/scripts/speedslider.js
@ -31,17 +31,17 @@
 MochaUI.extend({
    addUpLimitSlider: function(hashes) {
        if ($('uplimitSliderarea')) {
-            var windowOptions = MochaUI.Windows.windowOptions;
+            const windowOptions = MochaUI.Windows.windowOptions;
-            var sliderFirst = true;
+            const sliderFirst = true;
            // Get global upload limit
-            var maximum = 500;
+            let maximum = 500;
-            var req = new Request({
+            const req = new Request({
                url: 'api/v2/transfer/uploadLimit',
                method: 'post',
                data: {},
                onSuccess: function(data) {
                    if (data) {
-                        var tmp = data.toInt();
+                        const tmp = data.toInt();
                        if (tmp > 0) {
                            maximum = tmp / 1024.0;
                        }
@ -55,10 +55,10 @@ MochaUI.extend({
                    // Get torrents upload limit
                    // And create slider
                    if (hashes[0] == 'global') {
-                        var up_limit = maximum;
+                        let up_limit = maximum;
                        if (up_limit < 0) up_limit = 0;
                        maximum = 10000;
-                        var mochaSlide = new Slider($('uplimitSliderarea'), $('uplimitSliderknob'), {
+                        const mochaSlide = new Slider($('uplimitSliderarea'), $('uplimitSliderknob'), {
                            steps: maximum,
                            offset: 0,
                            initialStep: up_limit.round(),
@ -84,7 +84,7 @@ MochaUI.extend({
                        }
                    }
                    else {
-                        var req = new Request.JSON({
+                        const req = new Request.JSON({
                            url: 'api/v2/torrents/uploadLimit',
                            noCache : true,
                            method: 'post',
@ -93,14 +93,14 @@ MochaUI.extend({
                            },
                            onSuccess: function(data) {
                                if (data) {
-                                    var up_limit = data[hashes[0]];
+                                    let up_limit = data[hashes[0]];
-                                    for(var key in data)
+                                    for(const key in data)
                                        if (up_limit != data[key]) {
                                            up_limit = 0;
                                            break;
                                        }
                                    if (up_limit < 0) up_limit = 0;
-                                    var mochaSlide = new Slider($('uplimitSliderarea'), $('uplimitSliderknob'), {
+                                    const mochaSlide = new Slider($('uplimitSliderarea'), $('uplimitSliderknob'), {
                                        steps: maximum,
                                        offset: 0,
                                        initialStep: (up_limit / 1024.0).round(),
@ -135,17 +135,17 @@ MochaUI.extend({
    addDlLimitSlider: function(hashes) {
        if ($('dllimitSliderarea')) {
-            var windowOptions = MochaUI.Windows.windowOptions;
+            const windowOptions = MochaUI.Windows.windowOptions;
-            var sliderFirst = true;
+            const sliderFirst = true;
            // Get global upload limit
-            var maximum = 500;
+            let maximum = 500;
-            var req = new Request({
+            const req = new Request({
                url: 'api/v2/transfer/downloadLimit',
                method: 'post',
                data: {},
                onSuccess: function(data) {
                    if (data) {
-                        var tmp = data.toInt();
+                        const tmp = data.toInt();
                        if (tmp > 0) {
                            maximum = tmp / 1024.0;
                        }
@ -159,10 +159,10 @@ MochaUI.extend({
                    // Get torrents download limit
                    // And create slider
                    if (hashes[0] == 'global') {
-                        var dl_limit = maximum;
+                        let dl_limit = maximum;
                        if (dl_limit < 0) dl_limit = 0;
                        maximum = 10000;
-                        var mochaSlide = new Slider($('dllimitSliderarea'), $('dllimitSliderknob'), {
+                        const mochaSlide = new Slider($('dllimitSliderarea'), $('dllimitSliderknob'), {
                            steps: maximum,
                            offset: 0,
                            initialStep: dl_limit.round(),
@ -188,7 +188,7 @@ MochaUI.extend({
                        }
                    }
                    else {
-                        var req = new Request.JSON({
+                        const req = new Request.JSON({
                            url: 'api/v2/torrents/downloadLimit',
                            noCache : true,
                            method: 'post',
@ -197,14 +197,14 @@ MochaUI.extend({
                            },
                            onSuccess: function(data) {
                                if (data) {
-                                    var dl_limit = data[hashes[0]];
+                                    let dl_limit = data[hashes[0]];
-                                    for(var key in data)
+                                    for(const key in data)
                                        if (dl_limit != data[key]) {
                                            dl_limit = 0;
                                            break;
                                        }
                                    if (dl_limit < 0) dl_limit = 0;
-                                    var mochaSlide = new Slider($('dllimitSliderarea'), $('dllimitSliderknob'), {
+                                    const mochaSlide = new Slider($('dllimitSliderarea'), $('dllimitSliderknob'), {
                                        steps: maximum,
                                        offset: 0,
                                        initialStep: (dl_limit / 1024.0).round(),
--- a/src/webui/www/private/search.html
+++ b/src/webui/www/private/search.html
@ -153,42 +153,42 @@
 <script>
    'use strict';
-    var loadSearchResultsTimer;
+    let loadSearchResultsTimer;
-    var loadSearchPluginsTimer;
+    let loadSearchPluginsTimer;
-    var searchResultsRowId = 0;
+    let searchResultsRowId = 0;
-    var searchRunning = false;
+    let searchRunning = false;
-    var requestCount = 0;
+    let requestCount = 0;
-    var searchPlugins = [];
+    let searchPlugins = [];
-    var prevSearchPluginsResponse;
+    let prevSearchPluginsResponse;
-    var searchPattern = "";
+    let searchPattern = "";
-    var searchFilterPattern = "";
+    let searchFilterPattern = "";
-    var searchSeedsFilter = {
+    const searchSeedsFilter = {
        min: 0,
        max: 0
    };
-    var searchSizeFilter = {
+    const searchSizeFilter = {
        min: 0.00,
        minUnit: 2, // B = 0, KiB = 1, MiB = 2, GiB = 3, TiB = 4, PiB = 5, EiB = 6
        max: 0.00,
        maxUnit: 3
    };
-    var prevNameFilterValue;
+    let prevNameFilterValue;
-    var selectedCategory = "QBT_TR(All categories)QBT_TR[CONTEXT=SearchEngineWidget]";
+    let selectedCategory = "QBT_TR(All categories)QBT_TR[CONTEXT=SearchEngineWidget]";
-    var selectedPlugin = "all";
+    let selectedPlugin = "all";
-    var prevSelectedPlugin;
+    let prevSelectedPlugin;
-    var activeSearchId = null;
+    let activeSearchId = null;
-    var initSearchTab = function() {
+    const initSearchTab = function() {
        // load "Search in" preference from local storage
        $('searchInTorrentName').set('value', (localStorage.getItem('search_in_filter') === "names") ? "names" : "everywhere");
        searchResultsTable.setup('searchResultsTableDiv', 'searchResultsTableFixedHeaderDiv', null);
        getPlugins();
-        var searchInNameFilterTimer = null;
+        let searchInNameFilterTimer = null;
        // listen for changes to searchInNameFilter
        $('searchInNameFilter').addEvent('input', function() {
-            var value = $('searchInNameFilter').get("value");
+            const value = $('searchInNameFilter').get("value");
            if (value !== prevNameFilterValue) {
                prevNameFilterValue = value;
                clearTimeout(searchInNameFilterTimer);
@ -206,7 +206,7 @@
                    // accept enter key as a click
                    new Event(e).stop();
-                    var elem = e.event.srcElement;
+                    const elem = e.event.srcElement;
                    if (elem.className.contains("searchInputField")) {
                        $('startSearchButton').click();
                        return;
@ -231,7 +231,7 @@
        }).activate();
    };
-    var startSearch = function(pattern, category, plugins) {
+    const startSearch = function(pattern, category, plugins) {
        clearTimeout(loadSearchResultsTimer);
        searchResultsTable.clear();
        $('numSearchResultsVisible').set('html', searchResultsTable.getFilteredAndSortedRows().length);
@ -239,7 +239,7 @@
        searchResultsRowId = 0;
        requestCount = 0;
-        var url = new URI('api/v2/search/start');
+        const url = new URI('api/v2/search/start');
        new Request.JSON({
            url: url,
            noCache: true,
@ -258,8 +258,8 @@
        }).send();
    };
-    var stopSearch = function() {
+    const stopSearch = function() {
-        var url = new URI('api/v2/search/stop');
+        const url = new URI('api/v2/search/stop');
        new Request({
            url: url,
            noCache: true,
@ -273,11 +273,11 @@
        }).send();
    };
-    var startStopSearch = function() {
+    const startStopSearch = function() {
        if (!searchRunning || !activeSearchId) {
-            var pattern = $('searchPattern').getProperty('value').trim();
+            const pattern = $('searchPattern').getProperty('value').trim();
-            var category = $('categorySelect').getProperty('value');
+            let category = $('categorySelect').getProperty('value');
-            var plugins = $('pluginsSelect').getProperty('value');
+            const plugins = $('pluginsSelect').getProperty('value');
            if (!pattern || !category || !plugins) return;
            if (category === "QBT_TR(All categories)QBT_TR[CONTEXT=SearchEngineWidget]")
@ -293,22 +293,22 @@
        }
    };
-    var openSearchTorrentDescription = function() {
+    const openSearchTorrentDescription = function() {
        searchResultsTable.selectedRowsIds().each(function(rowId) {
            window.open(searchResultsTable.rows.get(rowId).full_data.descrLink, "_blank");
        });
    };
-    var copySearchTorrentUrl = function() {
+    const copySearchTorrentUrl = function() {
-        var urls = [];
+        const urls = [];
        searchResultsTable.selectedRowsIds().each(function(rowId) {
            urls.push(searchResultsTable.rows.get(rowId).full_data.descrLink);
        });
        return urls.join("\n");
    };
-    var downloadSearchTorrent = function() {
+    const downloadSearchTorrent = function() {
-        var urls = [];
+        const urls = [];
        searchResultsTable.selectedRowsIds().each(function(rowId) {
            urls.push(encodeURIComponent(searchResultsTable.rows.get(rowId).full_data.fileUrl));
        });
@ -319,8 +319,8 @@
        showDownloadPage(urls);
    };
-    var manageSearchPlugins = function() {
+    const manageSearchPlugins = function() {
-        var id = 'searchPlugins';
+        const id = 'searchPlugins';
        if (!$(id))
            new MochaUI.Window({
                id: id,
@ -345,16 +345,16 @@
            });
    };
-    var loadSearchPlugins = function() {
+    const loadSearchPlugins = function() {
        getPlugins();
        loadSearchPluginsTimer = loadSearchPlugins.delay(2000);
    };
-    var categorySelected = function() {
+    const categorySelected = function() {
        selectedCategory = $("categorySelect").get("value");
    };
-    var pluginSelected = function() {
+    const pluginSelected = function() {
        selectedPlugin = $("pluginsSelect").get("value");
        if (selectedPlugin !== prevSelectedPlugin) {
@ -363,23 +363,23 @@
        }
    };
-    var reselectCategory = function() {
+    const reselectCategory = function() {
-        for (var i = 0; i < $("categorySelect").options.length; ++i)
+        for (let i = 0; i < $("categorySelect").options.length; ++i)
            if ($("categorySelect").options[i].get("value") === selectedCategory)
                $("categorySelect").options[i].selected = true;
        categorySelected();
    };
-    var reselectPlugin = function() {
+    const reselectPlugin = function() {
-        for (var i = 0; i < $("pluginsSelect").options.length; ++i)
+        for (let i = 0; i < $("pluginsSelect").options.length; ++i)
            if ($("pluginsSelect").options[i].get("value") === selectedPlugin)
                $("pluginsSelect").options[i].selected = true;
        pluginSelected();
    };
-    var resetSearchState = function() {
+    const resetSearchState = function() {
        clearTimeout(loadSearchResultsTimer);
        $('startSearchButton').set('text', 'QBT_TR(Search)QBT_TR[CONTEXT=SearchEngineWidget]');
        searchResultsRowId = 0;
@ -387,9 +387,9 @@
        activeSearchId = null;
    };
-    var getSearchCategories = function() {
+    const getSearchCategories = function() {
-        var populateCategorySelect = function(categories) {
+        const populateCategorySelect = function(categories) {
-            var categoryHtml = [];
+            const categoryHtml = [];
            categories.each(function(category) {
                categoryHtml.push("<option>" + category + "</option>");
            });
@ -402,9 +402,9 @@
            $('categorySelect').set('html', categoryHtml.join(""));
        };
-        var selectedPlugin = $('pluginsSelect').get("value");
+        const selectedPlugin = $('pluginsSelect').get("value");
        if ((selectedPlugin === "all") || (selectedPlugin === "enabled")) {
-            var url = new URI('api/v2/search/categories');
+            const url = new URI('api/v2/search/categories');
            url.setData('name', selectedPlugin);
            new Request.JSON({
                url: url,
@ -416,8 +416,8 @@
            }).send();
        }
        else {
-            var plugins = ["QBT_TR(All categories)QBT_TR[CONTEXT=SearchEngineWidget]"];
+            let plugins = ["QBT_TR(All categories)QBT_TR[CONTEXT=SearchEngineWidget]"];
-            var plugin = getPlugin(selectedPlugin);
+            const plugin = getPlugin(selectedPlugin);
            if (plugin !== null)
                plugins = plugins.concat(plugin.supportedCategories);
@ -427,7 +427,7 @@
        reselectCategory();
    };
-    var getPlugins = function() {
+    const getPlugins = function() {
        new Request.JSON({
            url: new URI('api/v2/search/plugins'),
            noCache: true,
@ -437,11 +437,11 @@
                    prevSearchPluginsResponse = response;
                    searchPlugins = response;
-                    var pluginsHtml = [];
+                    const pluginsHtml = [];
                    pluginsHtml.push('<option value="enabled">QBT_TR(Only enabled)QBT_TR[CONTEXT=SearchEngineWidget]</option>');
                    pluginsHtml.push('<option value="all">QBT_TR(All plugins)QBT_TR[CONTEXT=SearchEngineWidget]</option>');
-                    var searchPluginsEmpty = (searchPlugins.length === 0);
+                    const searchPluginsEmpty = (searchPlugins.length === 0);
                    if (searchPluginsEmpty) {
                        $('searchResultsNoPlugins').style.display = "block";
                        $('searchResultsFilters').style.display = "none";
@ -453,9 +453,9 @@
                        $('searchResultsTableContainer').style.display = "block";
                        // sort plugins alphabetically
-                        var allPlugins = searchPlugins.sort(function(pluginA, pluginB) {
+                        const allPlugins = searchPlugins.sort(function(pluginA, pluginB) {
-                            var a = pluginA.fullName.toLowerCase();
+                            const a = pluginA.fullName.toLowerCase();
-                            var b = pluginB.fullName.toLowerCase();
+                            const b = pluginB.fullName.toLowerCase();
                            if (a < b) return -1;
                            if (a > b) return 1;
                            return 0;
@ -489,15 +489,15 @@
        }).send();
    };
-    var getPlugin = function(name) {
+    const getPlugin = function(name) {
-        for (var i = 0; i < searchPlugins.length; ++i)
+        for (let i = 0; i < searchPlugins.length; ++i)
            if (searchPlugins[i].name === name)
                return searchPlugins[i];
        return null;
    };
-    var searchInTorrentName = function() {
+    const searchInTorrentName = function() {
        if ($('searchInTorrentName').get('value') === "names")
            localStorage.setItem('search_in_filter', "names");
        else
@ -506,7 +506,7 @@
        searchFilterChanged();
    };
-    var resetFilters = function() {
+    const resetFilters = function() {
        // reset filters
        $('searchMinSeedsFilter').set('value', '0');
        $('searchMaxSeedsFilter').set('value', '0');
@ -516,14 +516,14 @@
        $('searchMaxSizePrefix').set('value', '3'); // GiB
    };
-    var searchSeedsFilterChanged = function() {
+    const searchSeedsFilterChanged = function() {
        searchSeedsFilter.min = $('searchMinSeedsFilter').get('value');
        searchSeedsFilter.max = $('searchMaxSeedsFilter').get('value');
        searchFilterChanged();
    };
-    var searchSizeFilterChanged = function() {
+    const searchSizeFilterChanged = function() {
        searchSizeFilter.min = $('searchMinSizeFilter').get('value');
        searchSizeFilter.minUnit = $('searchMinSizePrefix').get('value');
        searchSizeFilter.max = $('searchMaxSizeFilter').get('value');
@ -532,17 +532,17 @@
        searchFilterChanged();
    };
-    var searchSizeFilterPrefixChanged = function() {
+    const searchSizeFilterPrefixChanged = function() {
        if (($('searchMinSizeFilter').get('value') != 0) || ($('searchMaxSizeFilter').get('value') != 0))
            searchSizeFilterChanged();
    };
-    var searchFilterChanged = function() {
+    const searchFilterChanged = function() {
        searchResultsTable.updateTable();
        $('numSearchResultsVisible').set('html', searchResultsTable.getFilteredAndSortedRows().length);
    };
-    var setupSearchTableEvents = function(enable) {
+    const setupSearchTableEvents = function(enable) {
        if (enable)
            $$(".searchTableRow").each(function(target) {
                target.addEventListener('dblclick', downloadSearchTorrent, false);
@ -553,9 +553,9 @@
            });
    };
-    var loadSearchResultsData = function() {
+    const loadSearchResultsData = function() {
-        var maxResults = 500;
+        const maxResults = 500;
-        var url = new URI('api/v2/search/results');
+        const url = new URI('api/v2/search/results');
        new Request.JSON({
            url: url,
            noCache: true,
@ -589,10 +589,10 @@
                    setupSearchTableEvents(false);
                    if (response.results) {
-                        var results = response.results;
+                        const results = response.results;
-                        for (var i = 0; i < results.length; ++i) {
+                        for (let i = 0; i < results.length; ++i) {
-                            var result = results[i];
+                            const result = results[i];
-                            var row = {
+                            const row = {
                                rowId: searchResultsRowId,
                                descrLink: result.descrLink,
                                fileName: result.fileName,
@ -622,7 +622,7 @@
                    setupSearchTableEvents(true);
                }
-                var timeout = 1000;
+                let timeout = 1000;
                if (requestCount > 30)
                    timeout = 3000;
                else if (requestCount > 10)
@ -635,7 +635,7 @@
        }).send();
    };
-    var updateSearchResultsData = function() {
+    const updateSearchResultsData = function() {
        clearTimeout(loadSearchResultsTimer);
        loadSearchResultsTimer = loadSearchResultsData.delay(500);
    };
--- a/src/webui/www/private/searchplugins.html
+++ b/src/webui/www/private/searchplugins.html
@ -79,11 +79,11 @@
 <script>
    'use strict';
-    var searchPluginsTableContextMenu;
+    this.searchPluginsTableContextMenu = undefined;
-    var prevOffsetLeft;
+    this.prevOffsetLeft = undefined;
-    var prevOffsetTop;
+    this.prevOffsetTop = undefined;
-    var initSearchPlugins = function() {
+    this.initSearchPlugins = function() {
        searchPluginsTableContextMenu = new SearchPluginsTableContextMenu({
            targets: '.searchPluginsTableRow',
            menu: 'searchPluginsTableMenu',
@ -97,11 +97,11 @@
        updateSearchPluginsTable();
    };
-    var closeSearchWindow = function(id) {
+    this.closeSearchWindow = function(id) {
        window.parent.MochaUI.closeWindow(window.parent.$(id));
    };
-    var installPlugin = function(path) {
+    this.installPlugin = function(path) {
        new MochaUI.Window({
            id: 'installSearchPlugin',
            title: "QBT_TR(Install plugin)QBT_TR[CONTEXT=PluginSourceDlg]",
@ -117,9 +117,9 @@
        });
    };
-    var uninstallPlugin = function() {
+    this.uninstallPlugin = function() {
-        var plugins = searchPluginsTable.selectedRowsIds().join('|');
+        const plugins = searchPluginsTable.selectedRowsIds().join('|');
-        var url = new URI('api/v2/search/uninstallPlugin');
+        const url = new URI('api/v2/search/uninstallPlugin');
        new Request({
            url: url,
            noCache: true,
@ -130,13 +130,13 @@
        }).send();
    };
-    var enablePlugin = function() {
+    this.enablePlugin = function() {
-        var plugins = searchPluginsTable.selectedRowsIds();
+        const plugins = searchPluginsTable.selectedRowsIds();
-        var enable = true;
+        let enable = true;
        if (plugins && plugins.length)
            enable = !getPlugin(plugins[0]).enabled;
-        var url = new URI('api/v2/search/enablePlugin');
+        const url = new URI('api/v2/search/enablePlugin');
        new Request({
            url: url,
            noCache: true,
@ -148,8 +148,8 @@
        }).send();
    };
-    var checkForUpdates = function() {
+    this.checkForUpdates = function() {
-        var url = new URI('api/v2/search/updatePlugins');
+        const url = new URI('api/v2/search/updatePlugins');
        new Request({
            url: url,
            noCache: true,
@ -157,7 +157,7 @@
        }).send();
    };
-    var calculateContextMenuOffsets = function() {
+    this.calculateContextMenuOffsets = function() {
        prevOffsetLeft = document.getElementById("searchPlugins").getBoundingClientRect().left;
        prevOffsetTop = document.getElementById("searchPlugins").getBoundingClientRect().top;
@ -167,13 +167,13 @@
        };
    };
-    var updateSearchPluginsTableContextMenuOffset = function() {
+    this.updateSearchPluginsTableContextMenuOffset = function() {
        // only re-calculate if window has moved
        if ((prevOffsetLeft !== document.getElementById("searchPlugins").getBoundingClientRect().left) || (prevOffsetTop !== document.getElementById("searchPlugins").getBoundingClientRect().top))
            searchPluginsTableContextMenu.options.offsets = calculateContextMenuOffsets();
    };
-    var setupSearchPluginTableEvents = function(enable) {
+    this.setupSearchPluginTableEvents = function(enable) {
        if (enable)
            $$(".searchPluginsTableRow").each(function(target) {
                target.addEventListener('dblclick', enablePlugin, false);
@ -186,15 +186,15 @@
            });
    };
-    var updateSearchPluginsTable = function() {
+    this.updateSearchPluginsTable = function() {
        // clear event listeners
        setupSearchPluginTableEvents(false);
-        var oldPlugins = Object.keys(searchPluginsTable.rows);
+        const oldPlugins = Object.keys(searchPluginsTable.rows);
        // remove old rows from the table
-        for (var i = 0; i < oldPlugins.length; ++i) {
+        for (let i = 0; i < oldPlugins.length; ++i) {
-            var found = false;
+            let found = false;
-            for (var j = 0; j < searchPlugins.length; ++j) {
+            for (let j = 0; j < searchPlugins.length; ++j) {
                if (searchPlugins[j].name === oldPlugins[i]) {
                    found = true;
                    break;
@ -204,7 +204,7 @@
                searchPluginsTable.removeRow(oldPlugins[i]);
        }
-        for (var i = 0; i < searchPlugins.length; ++i) {
+        for (let i = 0; i < searchPlugins.length; ++i) {
            searchPlugins[i].rowId = searchPlugins[i].name;
            searchPluginsTable.updateRowData(searchPlugins[i]);
        }
--- a/src/webui/www/private/setlocation.html
+++ b/src/webui/www/private/setlocation.html
@ -30,7 +30,7 @@
        }).activate();
        window.addEvent('domready', function() {
-            var path = new URI().getData('path');
+            const path = new URI().getData('path');
            // set text field to current value
            if (path)
                $('setLocation').value = escapeHtml(decodeURIComponent(path));
@ -39,13 +39,13 @@
            $('setLocationButton').addEvent('click', function(e) {
                new Event(e).stop();
                // check field
-                var location = $('setLocation').value.trim();
+                const location = $('setLocation').value.trim();
                if (location === null || location === "") {
                    $('error_div').set('text', 'QBT_TR(Save path is empty)QBT_TR[CONTEXT=TorrentsController]');
                    return false;
                }
-                var hashesList = new URI().getData('hashes');
+                const hashesList = new URI().getData('hashes');
                new Request({
                    url: 'api/v2/torrents/setLocation',
                    method: 'post',
--- a/src/webui/www/private/shareratio.html
+++ b/src/webui/www/private/shareratio.html
@ -11,8 +11,8 @@
    <script>
        'use strict';
-        var UseGlobalLimit = -2;
+        const UseGlobalLimit = -2;
-        var NoLimit = -1;
+        const NoLimit = -1;
        new Keyboard({
            defaultEventType: 'keydown',
@ -33,10 +33,10 @@
        }).activate();
        window.addEvent('domready', function() {
-            var hashesList = new URI().getData('hashes').split('|');
+            const hashesList = new URI().getData('hashes').split('|');
-            var origValues = new URI().getData('orig').split('|');
+            const origValues = new URI().getData('orig').split('|');
-            var values = {
+            const values = {
                ratioLimit: friendlyFloat(origValues[0], 2),
                seedingTimeLimit: parseInt(origValues[1]),
                maxRatio: friendlyFloat(origValues[2], 2),
@ -74,9 +74,9 @@
                    return false;
                }
-                var shareLimit = getSelectedRadioValue('shareLimit');
+                const shareLimit = getSelectedRadioValue('shareLimit');
-                var ratioLimitValue = 0.00;
+                let ratioLimitValue = 0.00;
-                var seedingTimeLimitValue = 0;
+                let seedingTimeLimitValue = 0;
                if (shareLimit === 'default') {
                    ratioLimitValue = seedingTimeLimitValue = UseGlobalLimit;
@ -108,10 +108,10 @@
        });
        function getSelectedRadioValue(name) {
-            var radios = document.getElementsByName(name);
+            const radios = document.getElementsByName(name);
-            for (var i = 0; i < radios.length; ++i) {
+            for (let i = 0; i < radios.length; ++i) {
-                var radio = radios[i];
+                const radio = radios[i];
                if (radio.checked) {
                    return (radio).get('value');
                }
@ -119,17 +119,17 @@
        }
        function setSelectedRadioValue(name, value) {
-            var radios = document.getElementsByName(name);
+            const radios = document.getElementsByName(name);
-            for (var i = 0; i < radios.length; ++i) {
+            for (let i = 0; i < radios.length; ++i) {
-                var radio = radios[i];
+                const radio = radios[i];
                if (radio.value === value)
                    radio.checked = true;
            }
        }
        function shareLimitChanged() {
-            var customShareLimit = getSelectedRadioValue('shareLimit') === 'custom';
+            const customShareLimit = getSelectedRadioValue('shareLimit') === 'custom';
            $('setRatio').set('disabled', !customShareLimit);
            $('setMinutes').set('disabled', !customShareLimit);
--- a/src/webui/www/private/transferlist.html
+++ b/src/webui/www/private/transferlist.html
@ -19,7 +19,7 @@
    'use strict';
    //create a context menu
-    var torrentsTableContextMenu = new TorrentsTableContextMenu({
+    const torrentsTableContextMenu = new TorrentsTableContextMenu({
        targets: '.torrentsTableContextMenuTarget',
        menu: 'torrentsTableMenu',
        actions: {
--- a/src/webui/www/private/upload.html
+++ b/src/webui/www/private/upload.html
@ -127,7 +127,7 @@
    <script>
        'use strict';
-        var submitted = false;
+        let submitted = false;
        $('uploadForm').addEventListener("submit", function() {
            $('startTorrentHidden').value = $('startTorrent').checked ? 'false' : 'true';
--- a/src/webui/www/private/uploadlimit.html
+++ b/src/webui/www/private/uploadlimit.html
@ -24,9 +24,9 @@
        <script>
            'use strict';
-            var hashes = new URI().getData('hashes').split('|');
+            const hashes = new URI().getData('hashes').split('|');
-            var setUpLimit = function() {
+            const setUpLimit = function() {
-                var limit = $("uplimitUpdatevalue").value.toInt() * 1024;
+                const limit = $("uplimitUpdatevalue").value.toInt() * 1024;
                if (hashes[0] == "global") {
                    new Request({
                        url: 'api/v2/transfer/setUploadLimit',
--- a/src/webui/www/public/scripts/login.js
+++ b/src/webui/www/public/scripts/login.js
@ -38,9 +38,9 @@ document.addEventListener('DOMContentLoaded', function() {
 });
 function submitLoginForm() {
-    var errorMsgElement = document.getElementById('error_msg');
+    const errorMsgElement = document.getElementById('error_msg');
-    var xhr = new XMLHttpRequest();
+    const xhr = new XMLHttpRequest();
    xhr.open('POST', 'api/v2/auth/login', true);
    xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded; charset=utf-8');
    xhr.addEventListener('readystatechange', function() {
@ -57,9 +57,9 @@ function submitLoginForm() {
            : 'QBT_TR(Unable to log in, qBittorrent is probably unreachable.)QBT_TR[CONTEXT=HttpServer]';
    });
-    var usernameElement = document.getElementById('username');
+    const usernameElement = document.getElementById('username');
-    var passwordElement = document.getElementById('password');
+    const passwordElement = document.getElementById('password');
-    var queryString = "username=" + encodeURIComponent(usernameElement.value) + "&password=" + encodeURIComponent(passwordElement.value);
+    const queryString = "username=" + encodeURIComponent(usernameElement.value) + "&password=" + encodeURIComponent(passwordElement.value);
    xhr.send(queryString);
    // clear the field