diff --git a/src/webui/www/private/addtrackers.html b/src/webui/www/private/addtrackers.html
index 88322f492..9bebf810a 100644
--- a/src/webui/www/private/addtrackers.html
+++ b/src/webui/www/private/addtrackers.html
@@ -8,6 +8,8 @@
     <script src="scripts/lib/mootools-1.2-core-yc.js"></script>
     <script src="scripts/lib/mootools-1.2-more.js"></script>
     <script>
+        'use strict';
+
         window.addEvent('domready', function() {
             var setLocationKeyboardEvents = new Keyboard({
                 defaultEventType: 'keydown',
diff --git a/src/webui/www/private/confirmdeletion.html b/src/webui/www/private/confirmdeletion.html
index e03eb4652..da430660d 100644
--- a/src/webui/www/private/confirmdeletion.html
+++ b/src/webui/www/private/confirmdeletion.html
@@ -8,6 +8,8 @@
     <script src="scripts/lib/mootools-1.2-core-yc.js"></script>
     <script src="scripts/lib/mootools-1.2-more.js"></script>
     <script>
+        'use strict';
+
         var hashes = new URI().getData('hashes').split('|');
         window.addEvent('domready', function() {
             $('cancelBtn').focus();
diff --git a/src/webui/www/private/download.html b/src/webui/www/private/download.html
index 3d2bc6b0d..fdb0367b8 100644
--- a/src/webui/www/private/download.html
+++ b/src/webui/www/private/download.html
@@ -135,6 +135,8 @@
         </div>
     </form>
     <script>
+        'use strict';
+
         var encodedUrls = new URI().getData('urls');
         if (encodedUrls) {
             var urls = [];
diff --git a/src/webui/www/private/downloadlimit.html b/src/webui/www/private/downloadlimit.html
index e02902976..b10fdd67f 100644
--- a/src/webui/www/private/downloadlimit.html
+++ b/src/webui/www/private/downloadlimit.html
@@ -22,6 +22,8 @@
             <div class="clear"></div>
         </div>
         <script>
+            'use strict';
+
             var hashes = new URI().getData('hashes').split('|');
             setDlLimit = function() {
                 var limit = $("dllimitUpdatevalue").value.toInt() * 1024;
diff --git a/src/webui/www/private/filters.html b/src/webui/www/private/filters.html
index f3d91117f..7af5eaaa0 100644
--- a/src/webui/www/private/filters.html
+++ b/src/webui/www/private/filters.html
@@ -23,6 +23,8 @@
 </div>
 
 <script>
+    'use strict';
+
     var categoriesFilterContextMenu = new CategoriesFilterContextMenu({
         targets: '.categoriesFilterContextMenuTarget',
         menu: 'categoriesFilterMenu',
diff --git a/src/webui/www/private/newcategory.html b/src/webui/www/private/newcategory.html
index 273be490e..ea313a44e 100644
--- a/src/webui/www/private/newcategory.html
+++ b/src/webui/www/private/newcategory.html
@@ -9,6 +9,8 @@
     <script src="scripts/lib/mootools-1.2-more.js"></script>
     <script src="scripts/misc.js?locale=${LANG}"></script>
     <script>
+        'use strict';
+
         var newCategoryKeyboardEvents = new Keyboard({
             defaultEventType: 'keydown',
             events: {
diff --git a/src/webui/www/private/preferences.html b/src/webui/www/private/preferences.html
index 957afbe9e..35013dbf8 100644
--- a/src/webui/www/private/preferences.html
+++ b/src/webui/www/private/preferences.html
@@ -25,6 +25,8 @@
     </div>
 
     <script>
+        'use strict';
+
         // Tabs
         MochaUI.initializeTabs('preferencesTabs');
 
diff --git a/src/webui/www/private/preferences_content.html b/src/webui/www/private/preferences_content.html
index 2ae863e93..5eb2fa2b3 100644
--- a/src/webui/www/private/preferences_content.html
+++ b/src/webui/www/private/preferences_content.html
@@ -814,6 +814,8 @@
 <div style="text-align: center; margin-top: 1em;"><input type="button" value="QBT_TR(Save)QBT_TR[CONTEXT=HttpServer]" onclick="applyPreferences();" /></div>
 
 <script>
+    'use strict';
+
     // Downloads tab
     var WatchedFoldersTable = new HtmlTable($("watched_folders_tab"));
 
diff --git a/src/webui/www/private/properties_content.html b/src/webui/www/private/properties_content.html
index 2ec80038d..13be251ae 100644
--- a/src/webui/www/private/properties_content.html
+++ b/src/webui/www/private/properties_content.html
@@ -152,6 +152,8 @@
 </div>
 
 <script>
+    'use strict';
+
     torrentPeersTable.setup('torrentPeersTableDiv', 'torrentPeersTableFixedHeaderDiv', null);
     var selectedTab = $(getLocalStorageItem('selected_tab', 'PropGeneralLink'));
     if (selectedTab)
diff --git a/src/webui/www/private/rename.html b/src/webui/www/private/rename.html
index 5e200d630..2a8c9b925 100644
--- a/src/webui/www/private/rename.html
+++ b/src/webui/www/private/rename.html
@@ -9,6 +9,8 @@
     <script src="scripts/lib/mootools-1.2-more.js"></script>
     <script src="scripts/misc.js?locale=${LANG}"></script>
     <script>
+        'use strict';
+
         var renameKeyboardEvents = new Keyboard({
             defaultEventType: 'keydown',
             events: {
diff --git a/src/webui/www/private/scripts/client.js b/src/webui/www/private/scripts/client.js
index 1901a6296..dd186c9f7 100644
--- a/src/webui/www/private/scripts/client.js
+++ b/src/webui/www/private/scripts/client.js
@@ -22,6 +22,8 @@
  * THE SOFTWARE.
  */
 
+'use strict';
+
 torrentsTable = new TorrentsTable();
 torrentPeersTable = new TorrentPeersTable();
 searchResultsTable = new SearchResultsTable();
diff --git a/src/webui/www/private/scripts/contextmenu.js b/src/webui/www/private/scripts/contextmenu.js
index b41c9e538..bbf9659be 100644
--- a/src/webui/www/private/scripts/contextmenu.js
+++ b/src/webui/www/private/scripts/contextmenu.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var lastShownContexMenu = null;
 var ContextMenu = new Class({
     //implements
diff --git a/src/webui/www/private/scripts/download.js b/src/webui/www/private/scripts/download.js
index 049e98741..643c32548 100644
--- a/src/webui/www/private/scripts/download.js
+++ b/src/webui/www/private/scripts/download.js
@@ -21,6 +21,8 @@
  * THE SOFTWARE.
  */
 
+'use strict';
+
 var categories = {};
 var defaultSavePath = "";
 
diff --git a/src/webui/www/private/scripts/dynamicTable.js b/src/webui/www/private/scripts/dynamicTable.js
index a07fcbed5..ba98f7c66 100644
--- a/src/webui/www/private/scripts/dynamicTable.js
+++ b/src/webui/www/private/scripts/dynamicTable.js
@@ -31,6 +31,8 @@
 
  **************************************************************/
 
+'use strict';
+
 var DynamicTableHeaderContextMenuClass = null;
 var ProgressColumnWidth = -1;
 
diff --git a/src/webui/www/private/scripts/misc.js b/src/webui/www/private/scripts/misc.js
index 8af81ce15..f08ea57ff 100644
--- a/src/webui/www/private/scripts/misc.js
+++ b/src/webui/www/private/scripts/misc.js
@@ -1,3 +1,5 @@
+'use strict';
+
 /*
  * JS counterpart of the function in src/misc.cpp
  */
diff --git a/src/webui/www/private/scripts/mocha-init.js b/src/webui/www/private/scripts/mocha-init.js
index 9ca0d8fd4..6643e7048 100644
--- a/src/webui/www/private/scripts/mocha-init.js
+++ b/src/webui/www/private/scripts/mocha-init.js
@@ -8,6 +8,8 @@
     it in the onContentLoaded function of the new window.
 
    ----------------------------------------------------------------- */
+'use strict';
+
 /* Define localStorage object for older browsers */
 if (typeof localStorage == 'undefined') {
     window['localStorage'] = {
diff --git a/src/webui/www/private/scripts/progressbar.js b/src/webui/www/private/scripts/progressbar.js
index de5edf68c..ed152249d 100644
--- a/src/webui/www/private/scripts/progressbar.js
+++ b/src/webui/www/private/scripts/progressbar.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var ProgressBar = new Class({
     initialize: function(value, parameters) {
         var vals = {
diff --git a/src/webui/www/private/scripts/prop-files.js b/src/webui/www/private/scripts/prop-files.js
index ddd567685..b117adf8c 100644
--- a/src/webui/www/private/scripts/prop-files.js
+++ b/src/webui/www/private/scripts/prop-files.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var is_seed = true;
 var current_hash = "";
 
diff --git a/src/webui/www/private/scripts/prop-general.js b/src/webui/www/private/scripts/prop-general.js
index 40745154d..29de5ef8e 100644
--- a/src/webui/www/private/scripts/prop-general.js
+++ b/src/webui/www/private/scripts/prop-general.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var clearData = function() {
     $('time_elapsed').set('html', '');
     $('eta').set('html', '');
diff --git a/src/webui/www/private/scripts/prop-trackers.js b/src/webui/www/private/scripts/prop-trackers.js
index 84d053153..df6c471a0 100644
--- a/src/webui/www/private/scripts/prop-trackers.js
+++ b/src/webui/www/private/scripts/prop-trackers.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var trackersDynTable = new Class({
 
     initialize: function() {},
diff --git a/src/webui/www/private/scripts/prop-webseeds.js b/src/webui/www/private/scripts/prop-webseeds.js
index 5819a99ac..291574043 100644
--- a/src/webui/www/private/scripts/prop-webseeds.js
+++ b/src/webui/www/private/scripts/prop-webseeds.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var webseedsDynTable = new Class({
 
     initialize: function() {},
diff --git a/src/webui/www/private/setlocation.html b/src/webui/www/private/setlocation.html
index 455224fc2..bd43215eb 100644
--- a/src/webui/www/private/setlocation.html
+++ b/src/webui/www/private/setlocation.html
@@ -9,6 +9,8 @@
     <script src="scripts/lib/mootools-1.2-more.js"></script>
     <script src="scripts/misc.js?locale=${LANG}"></script>
     <script>
+        'use strict';
+
         var setLocationKeyboardEvents = new Keyboard({
             defaultEventType: 'keydown',
             events: {
diff --git a/src/webui/www/private/shareratio.html b/src/webui/www/private/shareratio.html
index cf8b025c3..bc56f7974 100644
--- a/src/webui/www/private/shareratio.html
+++ b/src/webui/www/private/shareratio.html
@@ -9,6 +9,8 @@
     <script src="scripts/lib/mootools-1.2-more.js"></script>
     <script src="scripts/misc.js?locale=${LANG}"></script>
     <script>
+        'use strict';
+
         var UseGlobalLimit = -2;
         var NoLimit = -1;
 
diff --git a/src/webui/www/private/transferlist.html b/src/webui/www/private/transferlist.html
index dffd7c472..86345ffc3 100644
--- a/src/webui/www/private/transferlist.html
+++ b/src/webui/www/private/transferlist.html
@@ -16,6 +16,8 @@
 </div>
 
 <script>
+    'use strict';
+
     //create a context menu
     var torrentsTableContextMenu = new TorrentsTableContextMenu({
         targets: '.torrentsTableContextMenuTarget',
diff --git a/src/webui/www/private/upload.html b/src/webui/www/private/upload.html
index 3adacebae..bed0093eb 100644
--- a/src/webui/www/private/upload.html
+++ b/src/webui/www/private/upload.html
@@ -122,6 +122,8 @@
         </fieldset>
     </form>
     <script>
+        'use strict';
+
         var submitted = false;
 
         $('uploadForm').addEventListener("submit", function() {
diff --git a/src/webui/www/private/uploadlimit.html b/src/webui/www/private/uploadlimit.html
index 1f0a5a93b..4b0b22515 100644
--- a/src/webui/www/private/uploadlimit.html
+++ b/src/webui/www/private/uploadlimit.html
@@ -22,6 +22,8 @@
             <div class="clear"></div>
         </div>
         <script>
+            'use strict';
+
             var hashes = new URI().getData('hashes').split('|');
             setUpLimit = function() {
                 var limit = $("uplimitUpdatevalue").value.toInt() * 1024;
diff --git a/src/webui/www/public/login.html b/src/webui/www/public/login.html
index 1982f4788..929a497d4 100644
--- a/src/webui/www/public/login.html
+++ b/src/webui/www/public/login.html
@@ -8,6 +8,8 @@
     <link rel="stylesheet" type="text/css" href="css/login.css" />
     <script src="scripts/lib/mootools-1.2-core-yc.js"></script>
     <script>
+        'use strict';
+
         window.onload = function() {
             $('username').focus();
             $('username').select();