diff --git a/lib/yui/chooserdialogue/chooserdialogue.js b/lib/yui/chooserdialogue/chooserdialogue.js
index cad6f1f0b54..6f8ceecc307 100644
--- a/lib/yui/chooserdialogue/chooserdialogue.js
+++ b/lib/yui/chooserdialogue/chooserdialogue.js
@@ -2,7 +2,7 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
 
     var CHOOSERDIALOGUE = function() {
         CHOOSERDIALOGUE.superclass.constructor.apply(this, arguments);
-    }
+    };
 
     Y.extend(CHOOSERDIALOGUE, Y.Base, {
         // The panel widget
@@ -36,7 +36,8 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
             }
 
             // Set Default options
-            var params = {
+            var paramkey,
+                params = {
                 bodyContent : this.bodycontent.get('innerHTML'),
                 headerContent : this.headercontent.get('innerHTML'),
                 width : '540px',
@@ -79,13 +80,14 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
          * @return void
          */
         display_chooser : function (e) {
+            var bb, dialogue, thisevent;
             this.prepare_chooser();
 
             // Stop the default event actions before we proceed
             e.preventDefault();
 
-            var bb = this.panel.get('boundingBox');
-            var dialogue = this.container.one('.alloptions');
+            bb = this.panel.get('boundingBox');
+            dialogue = this.container.one('.alloptions');
 
             // Get the overflow setting when the chooser was opened - we
             // may need this later
@@ -95,16 +97,14 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
                 this.initialoverflow = Y.one('body').getStyle('overflow');
             }
 
-            var thisevent;
-
             // This will detect a change in orientation and retrigger centering
-            thisevent = Y.one('document').on('orientationchange', function(e) {
+            thisevent = Y.one('document').on('orientationchange', function() {
                 this.center_dialogue(dialogue);
             }, this);
             this.listenevents.push(thisevent);
 
             // Detect window resizes (most browsers)
-            thisevent = Y.one('window').on('resize', function(e) {
+            thisevent = Y.one('window').on('resize', function() {
                 this.center_dialogue(dialogue);
             }, this);
             this.listenevents.push(thisevent);
@@ -128,7 +128,7 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
             }, this);
             this.listenevents.push(thisevent);
 
-            this.container.one('form').on('submit', function(e) {
+            this.container.one('form').on('submit', function() {
                 // Prevent duplicate submissions on submit
                 this.submitbutton.setAttribute('disabled', 'disabled');
                 this.options.setAttribute('disabled', 'disabled');
@@ -181,7 +181,8 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
         cancel_listenevents : function () {
             // Detach all listen events to prevent duplicate triggers
             var thisevent;
-            while (thisevent = this.listenevents.shift()) {
+            while (this.listenevents.length) {
+                thisevent = this.listenevents.shift();
                 thisevent.detach();
             }
         },
@@ -196,15 +197,15 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
          * @return void
          */
         center_dialogue : function(dialogue) {
-            var bb = this.panel.get('boundingBox');
-
-            var winheight = bb.get('winHeight');
-            var winwidth = bb.get('winWidth');
-            var offsettop = 0;
+            var bb = this.panel.get('boundingBox'),
+                winheight = bb.get('winHeight'),
+                winwidth = bb.get('winWidth'),
+                offsettop = 0,
+                newheight, totalheight, dialoguetop, dialoguewidth, dialogueleft;
 
             // Try and set a sensible max-height -- this must be done before setting the top
             // Set a default height of 640px
-            var newheight = this.get('maxheight');
+            newheight = this.get('maxheight');
             if (winheight <= newheight) {
                 // Deal with smaller window sizes
                 if (winheight <= this.get('minheight')) {
@@ -236,13 +237,13 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
 
             // Take off 15px top and bottom for borders, plus 40px each for the title and button area before setting the
             // new max-height
-            var totalheight = newheight;
+            totalheight = newheight;
             newheight = newheight - (15 + 15 + 40 + 40);
             dialogue.setStyle('max-height', newheight + 'px');
             dialogue.setStyle('height', newheight + 'px');
 
             // Re-calculate the location now that we've changed the size
-            var dialoguetop = Math.max(12, ((winheight - totalheight) / 2)) + offsettop;
+            dialoguetop = Math.max(12, ((winheight - totalheight) / 2)) + offsettop;
 
             // We need to set the height for the yui3-widget - can't work
             // out what we're setting at present -- shoud be the boudingBox
@@ -251,13 +252,13 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
             // Calculate the left location of the chooser
             // We don't set a minimum width in the same way as we do height as the width would be far lower than the
             // optimal width for moodle anyway.
-            var dialoguewidth = bb.get('offsetWidth');
-            var dialogueleft = (winwidth - dialoguewidth) / 2;
+            dialoguewidth = bb.get('offsetWidth');
+            dialogueleft = (winwidth - dialoguewidth) / 2;
             bb.setStyle('left', dialogueleft + 'px');
         },
 
         handle_key_press : function(e) {
-            if (e.keyCode == 27) {
+            if (e.keyCode === 27) {
                 this.cancel_popup(e);
             }
         },
@@ -283,7 +284,7 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
             this.panel.hide();
         },
 
-        check_options : function(e) {
+        check_options : function() {
             // Check which options are set, and change the parent class
             // to show/hide help as required
             this.options.each(function(thisoption) {
@@ -305,7 +306,7 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
             }, this);
         },
 
-        option_selected : function(e) {
+        option_selected : function() {
         }
     },
     {