diff --git a/core/misc/ajax.js b/core/misc/ajax.js
index c35241c..8561462 100644
--- a/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Provides Ajax page updating via jQuery $.ajax (Asynchronous JavaScript and XML).
  *
diff --git a/core/misc/authorize.js b/core/misc/authorize.js
index d522a5b..aa4575d 100644
--- a/core/misc/authorize.js
+++ b/core/misc/authorize.js
@@ -1,4 +1,3 @@
-
 /**
  * @file
  * Conditionally hide or show the appropriate settings and saved defaults
@@ -7,6 +6,8 @@
 
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.authorizeFileTransferForm = {
   attach: function(context) {
     $('#edit-connection-settings-authorize-filetransfer-default').change(function() {
diff --git a/core/misc/autocomplete.js b/core/misc/autocomplete.js
index a4f6335..8b0dd72 100644
--- a/core/misc/autocomplete.js
+++ b/core/misc/autocomplete.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Attaches the autocomplete behavior to all required fields.
  */
diff --git a/core/misc/batch.js b/core/misc/batch.js
index 6d28b69..b83776d 100644
--- a/core/misc/batch.js
+++ b/core/misc/batch.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Attaches the batch behavior to progress bars.
  */
diff --git a/core/misc/collapse.js b/core/misc/collapse.js
index 28281a1..109ac59 100644
--- a/core/misc/collapse.js
+++ b/core/misc/collapse.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Toggle the visibility of a fieldset using smooth animations.
  */
@@ -58,7 +60,7 @@ Drupal.behaviors.collapse = {
     $(context).find('fieldset.collapsible').once('collapse', function () {
       var $fieldset = $(this);
       // Expand fieldset if there are errors inside, or if it contains an
-      // element that is targeted by the uri fragment identifier. 
+      // element that is targeted by the uri fragment identifier.
       var anchor = location.hash && location.hash != '#' ? ', ' + location.hash : '';
       if ($fieldset.find('.error' + anchor).length) {
         $fieldset.removeClass('collapsed');
diff --git a/core/misc/drupal.js b/core/misc/drupal.js
index c7917b0..9196475 100644
--- a/core/misc/drupal.js
+++ b/core/misc/drupal.js
@@ -5,6 +5,8 @@ jQuery.noConflict();
 
 (function ($) {
 
+"use strict";
+
 /**
  * Attach all registered behaviors to a page element.
  *
diff --git a/core/misc/form.js b/core/misc/form.js
index 4dc5b8c..0e7cf7b 100644
--- a/core/misc/form.js
+++ b/core/misc/form.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Retrieves the summary for the first element.
  */
diff --git a/core/misc/machine-name.js b/core/misc/machine-name.js
index ffe774f..3cb7351 100644
--- a/core/misc/machine-name.js
+++ b/core/misc/machine-name.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Attach the machine-readable name form element behavior.
  */
diff --git a/core/misc/progress.js b/core/misc/progress.js
index b0e125c..343b9ad 100644
--- a/core/misc/progress.js
+++ b/core/misc/progress.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * A progressbar object. Initialized with the given id. Must be inserted into
  * the DOM afterwards through progressBar.element.
diff --git a/core/misc/states.js b/core/misc/states.js
index 30b63ba..65ee9da 100644
--- a/core/misc/states.js
+++ b/core/misc/states.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * The base States namespace.
  *
diff --git a/core/misc/tabledrag.js b/core/misc/tabledrag.js
index 16800e0..273dcc1 100644
--- a/core/misc/tabledrag.js
+++ b/core/misc/tabledrag.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Drag and drop table rows with field manipulation.
  *
diff --git a/core/misc/tableheader.js b/core/misc/tableheader.js
index aa1c8bb..225cb73 100644
--- a/core/misc/tableheader.js
+++ b/core/misc/tableheader.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Attaches sticky table headers.
  */
diff --git a/core/misc/tableselect.js b/core/misc/tableselect.js
index b7011e0..2bf708e 100644
--- a/core/misc/tableselect.js
+++ b/core/misc/tableselect.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.tableSelect = {
   attach: function (context, settings) {
     // Select the inner-most table in case of nested tables.
diff --git a/core/misc/timezone.js b/core/misc/timezone.js
index 62b7d4b..787cfcf 100644
--- a/core/misc/timezone.js
+++ b/core/misc/timezone.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Set the client's system time zone as default values of form fields.
  */
diff --git a/core/misc/vertical-tabs.js b/core/misc/vertical-tabs.js
index 65e5683..baae1d1 100644
--- a/core/misc/vertical-tabs.js
+++ b/core/misc/vertical-tabs.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * This script transforms a set of fieldsets into a stack of vertical
  * tabs. Another tab pane can be selected by clicking on the respective
diff --git a/core/modules/block/block.js b/core/modules/block/block.js
index dabb570..e200017 100644
--- a/core/modules/block/block.js
+++ b/core/modules/block/block.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Provide the summary information for the block settings vertical tabs.
  */
diff --git a/core/modules/book/book.js b/core/modules/book/book.js
index e6ab4fa..b7a6713 100644
--- a/core/modules/book/book.js
+++ b/core/modules/book/book.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.bookFieldsetSummaries = {
   attach: function (context) {
     $(context).find('fieldset.book-outline-form').drupalSetSummary(function (context) {
diff --git a/core/modules/color/color.js b/core/modules/color/color.js
index d833a4b..31c526e 100644
--- a/core/modules/color/color.js
+++ b/core/modules/color/color.js
@@ -5,6 +5,8 @@
 
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.color = {
   attach: function (context, settings) {
     var i, j, colors, field_name;
diff --git a/core/modules/color/preview.js b/core/modules/color/preview.js
index 69c3897..9e19985 100644
--- a/core/modules/color/preview.js
+++ b/core/modules/color/preview.js
@@ -4,6 +4,9 @@
  */
 
 (function ($) {
+
+  "use strict";
+
   Drupal.color = {
     callback: function(context, settings, form, farb, height, width) {
       // Solid background.
diff --git a/core/modules/comment/comment-node-form.js b/core/modules/comment/comment-node-form.js
index 51ea492..0249d96 100644
--- a/core/modules/comment/comment-node-form.js
+++ b/core/modules/comment/comment-node-form.js
@@ -5,6 +5,8 @@
 
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.commentFieldsetSummaries = {
   attach: function (context) {
     var $context = $(context);
diff --git a/core/modules/contextual/contextual.js b/core/modules/contextual/contextual.js
index 1c3305f..c8cc0e4 100644
--- a/core/modules/contextual/contextual.js
+++ b/core/modules/contextual/contextual.js
@@ -5,6 +5,8 @@
 
 (function ($) {
 
+"use strict";
+
 Drupal.contextualLinks = Drupal.contextualLinks || {};
 
 /**
diff --git a/core/modules/dashboard/dashboard.js b/core/modules/dashboard/dashboard.js
index 39d87c2..e1a43e0 100644
--- a/core/modules/dashboard/dashboard.js
+++ b/core/modules/dashboard/dashboard.js
@@ -5,6 +5,8 @@
 
 (function ($) {
 
+"use strict";
+
 /**
  * Implements Drupal.behaviors for the Dashboard module.
  */
diff --git a/core/modules/field/modules/text/text.js b/core/modules/field/modules/text/text.js
index 8527355..be6aa49 100644
--- a/core/modules/field/modules/text/text.js
+++ b/core/modules/field/modules/text/text.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Auto-hide summary textarea if empty and show hide and unhide links.
  */
diff --git a/core/modules/field_ui/field_ui.js b/core/modules/field_ui/field_ui.js
index 6de5c15..7cdfacc 100644
--- a/core/modules/field_ui/field_ui.js
+++ b/core/modules/field_ui/field_ui.js
@@ -2,9 +2,11 @@
  * @file
  * Attaches the behaviors for the Field UI module.
  */
- 
+
 (function($) {
 
+"use strict";
+
 Drupal.behaviors.fieldUIFieldOverview = {
   attach: function (context, settings) {
     $(context).find('table#field-overview').once('field-overview', function () {
diff --git a/core/modules/file/file.js b/core/modules/file/file.js
index a934afe..cec3fe8 100644
--- a/core/modules/file/file.js
+++ b/core/modules/file/file.js
@@ -9,6 +9,8 @@
 
 (function ($) {
 
+"use strict";
+
 /**
  * Attach behaviors to managed file element upload fields.
  */
diff --git a/core/modules/filter/filter.admin.js b/core/modules/filter/filter.admin.js
index 43cda26..b002041 100644
--- a/core/modules/filter/filter.admin.js
+++ b/core/modules/filter/filter.admin.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.filterStatus = {
   attach: function (context, settings) {
     var $context = $(context);
diff --git a/core/modules/filter/filter.js b/core/modules/filter/filter.js
index db5f42a..9482737 100644
--- a/core/modules/filter/filter.js
+++ b/core/modules/filter/filter.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Automatically display the guidelines of the selected text format.
  */
diff --git a/core/modules/locale/locale.datepicker.js b/core/modules/locale/locale.datepicker.js
index 81f1e17..024c1e2 100644
--- a/core/modules/locale/locale.datepicker.js
+++ b/core/modules/locale/locale.datepicker.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 $.datepicker.regional['drupal-locale'] = {
   closeText: Drupal.t('Done'),
   prevText: Drupal.t('Prev'),
diff --git a/core/modules/menu/menu.admin.js b/core/modules/menu/menu.admin.js
index 4e5bf07..9eda4da 100644
--- a/core/modules/menu/menu.admin.js
+++ b/core/modules/menu/menu.admin.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.menuChangeParentItems = {
   attach: function (context, settings) {
     $('fieldset#edit-menu input').each(function () {
diff --git a/core/modules/menu/menu.js b/core/modules/menu/menu.js
index f315e7a..f3bfb1c 100644
--- a/core/modules/menu/menu.js
+++ b/core/modules/menu/menu.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.menuFieldsetSummaries = {
   attach: function (context) {
     $(context).find('fieldset.menu-link-form').drupalSetSummary(function (context) {
diff --git a/core/modules/node/content_types.js b/core/modules/node/content_types.js
index 43cfa37..5c1c44e 100644
--- a/core/modules/node/content_types.js
+++ b/core/modules/node/content_types.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.contentTypes = {
   attach: function (context) {
     var $context = $(context);
diff --git a/core/modules/node/node.js b/core/modules/node/node.js
index 8990164..0899d3c 100644
--- a/core/modules/node/node.js
+++ b/core/modules/node/node.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.nodeFieldsetSummaries = {
   attach: function (context) {
     var $context = $(context);
diff --git a/core/modules/openid/openid.js b/core/modules/openid/openid.js
index 754efb1..53a0cb3 100644
--- a/core/modules/openid/openid.js
+++ b/core/modules/openid/openid.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.openid = {
   attach: function (context) {
     var $context = $(context);
diff --git a/core/modules/overlay/overlay-child.js b/core/modules/overlay/overlay-child.js
index ff111d8..29a9790 100644
--- a/core/modules/overlay/overlay-child.js
+++ b/core/modules/overlay/overlay-child.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Attach the child dialog behavior to new content.
  */
diff --git a/core/modules/overlay/overlay-parent.js b/core/modules/overlay/overlay-parent.js
index 19d2d64..e20682a 100644
--- a/core/modules/overlay/overlay-parent.js
+++ b/core/modules/overlay/overlay-parent.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Open the overlay, or load content into it, when an admin link is clicked.
  */
diff --git a/core/modules/path/path.js b/core/modules/path/path.js
index b20378e..41b6e8f 100644
--- a/core/modules/path/path.js
+++ b/core/modules/path/path.js
@@ -4,6 +4,8 @@
  */
 (function ($) {
 
+"use strict";
+
 Drupal.behaviors.pathFieldsetSummaries = {
   attach: function (context) {
     $(context).find('fieldset.path-form').drupalSetSummary(function (context) {
diff --git a/core/modules/shortcut/shortcut.admin.js b/core/modules/shortcut/shortcut.admin.js
index 2647f34..4530df5 100644
--- a/core/modules/shortcut/shortcut.admin.js
+++ b/core/modules/shortcut/shortcut.admin.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Handle the concept of a fixed number of slots.
  *
diff --git a/core/modules/system/system.cron.js b/core/modules/system/system.cron.js
index af17dab..a35a914 100644
--- a/core/modules/system/system.cron.js
+++ b/core/modules/system/system.cron.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Checks to see if the cron should be automatically run.
  */
diff --git a/core/modules/system/system.js b/core/modules/system/system.js
index 98da1a6..8e22e4e 100644
--- a/core/modules/system/system.js
+++ b/core/modules/system/system.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Show/hide the 'Email site administrator when updates are available' checkbox
  * on the install page.
diff --git a/core/modules/taxonomy/taxonomy.js b/core/modules/taxonomy/taxonomy.js
index 035dc29..0fe6e9a 100644
--- a/core/modules/taxonomy/taxonomy.js
+++ b/core/modules/taxonomy/taxonomy.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Move a block in the blocks table from one region to another via select list.
  *
diff --git a/core/modules/toolbar/toolbar.js b/core/modules/toolbar/toolbar.js
index d345284..ee8bddb 100644
--- a/core/modules/toolbar/toolbar.js
+++ b/core/modules/toolbar/toolbar.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 Drupal.toolbar = Drupal.toolbar || {};
 
 /**
diff --git a/core/modules/user/user.js b/core/modules/user/user.js
index 59a178e..147c4c2 100644
--- a/core/modules/user/user.js
+++ b/core/modules/user/user.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Attach handlers to evaluate the strength of any password fields and to check
  * that its confirmation is correct.
@@ -157,6 +159,7 @@ Drupal.evaluatePasswordStrength = function (password, translate) {
     strength = 5;
   }
 
+  var indicatorText;
   // Based on the strength, work out what text should be shown by the password strength meter.
   if (strength < 60) {
     indicatorText = translate.weak;
diff --git a/core/modules/user/user.permissions.js b/core/modules/user/user.permissions.js
index 896c936..4b6d4c9 100644
--- a/core/modules/user/user.permissions.js
+++ b/core/modules/user/user.permissions.js
@@ -1,5 +1,7 @@
 (function ($) {
 
+"use strict";
+
 /**
  * Shows checked and disabled checkboxes for inherited permissions.
  */
diff --git a/core/themes/bartik/color/preview.js b/core/themes/bartik/color/preview.js
index aeb4171..531deec 100644
--- a/core/themes/bartik/color/preview.js
+++ b/core/themes/bartik/color/preview.js
@@ -2,8 +2,10 @@
  * @file
  * Preview for the Bartik theme.
  */
-
 (function ($) {
+
+  "use strict";
+
   Drupal.color = {
     logoChanged: false,
     callback: function(context, settings, form, farb, height, width) {