Fixed a few js memory leaks in EditSurvey page (SimpleEditor appears to

have a memory leak of its own which we either need to get fixed or
work-around).

www/extras/wobject/Survey/editsurvey.js

@@ -9,6 +9,16 @@ Survey.Data = (function(){
     var focus;
     var lastId = -1;
 	
+	// Keep references to widgets here so that we can destory any instances before
+	// creating new ones (to avoid memory leaks)
+	var autoComplete;
+	var sButton, qButton, aButton;
+
+	function purgeNode(node) {
+		YAHOO.util.Event.purgeElement(node, true);
+		document.getElementById(node).innerHTML = '';
+	}
+
     return {
         dragDrop: function(did){
 
@@ -57,6 +67,11 @@ Survey.Data = (function(){
             else {
                 lastId = d.address;
             }
+
+			// First purge any event handlers bound to sections node..
+			YAHOO.util.Event.purgeElement('sections', true);
+
+			// Now we can re-write its innerHTML without fear of memory leaks
             document.getElementById('sections').innerHTML = d.ddhtml;
 
             //add event handlers for if a tag is clicked
@@ -68,28 +83,25 @@ Survey.Data = (function(){
 				}
             }
 
-            //add the add object buttons
+			sButton && sButton.destroy();
-            //        if(d.buttons['section']){
+			sButton = new YAHOO.widget.Button({
-            document.getElementById('addSection').innerHTML = '';
-            document.getElementById('addQuestion').innerHTML = '';
-            document.getElementById('addAnswer').innerHTML = '';
-            var sButton = new YAHOO.widget.Button({
                 label: "Add Section",
                 id: "addsection",
                 container: "addSection"
             });
             sButton.on("click", this.addSection);
-            //        }
+
-            //        if(d.buttons['question']){
+			qButton && qButton.destroy();
-            var qButton = new YAHOO.widget.Button({
+            qButton = new YAHOO.widget.Button({
                 label: "Add Question",
                 id: "addquestion",
                 container: "addQuestion"
             });
             qButton.on("click", this.addQuestion, d.buttons.question);
-            //        }
+
             if (d.buttons.answer) {
-                var aButton = new YAHOO.widget.Button({
+				aButton && aButton.destroy();
+                aButton = new YAHOO.widget.Button({
                     label: "Add Answer",
                     id: "addanswer",
                     container: "addAnswer"
@@ -102,12 +114,16 @@ Survey.Data = (function(){
 
                 // build the goto auto-complete widget
                 if (d.gotoTargets && document.getElementById('goto')) {
-                    var ds = new YAHOO.util.LocalDataSource(d.gotoTargets);
+                    var ds =  new YAHOO.util.LocalDataSource(d.gotoTargets);
-                    var ac = new YAHOO.widget.AutoComplete('goto', 'goto-yui-ac-container', ds);
+                    autoComplete = new YAHOO.widget.AutoComplete('goto', 'goto-yui-ac-container', ds);
                 }
             }
             else {
-                document.getElementById('edit').innerHTML = "";
+				Survey.ObjectTemplate.unloadObject();
+				if (autoComplete) {
+					autoComplete.destroy();
+					autoComplete = null;
+				}
             }
             lastDataSet = d;
         },

www/extras/wobject/Survey/editsurvey/object.js

@@ -6,13 +6,30 @@ if (typeof Survey === "undefined") {
 
 Survey.ObjectTemplate = (function(){
 
-    var editor;
+	// Keep references to widgets here so that we can destory any instances before
+	// creating new ones (to avoid memory leaks)
     var dialog;
+    var editor;
 
     return {
     
-        loadObject: function(html, type){
+        unloadObject: function(){
+            // First destory the editor..
+            if (editor) {
+				editor.destroy();
+				editor = null;
+			}
             
+            // And then the Dialog that contains it.
+            if (dialog) {
+				dialog.destroy();
+				dialog = null;
+			}
+        },
+
+        loadObject: function(html, type){
+            // Make sure we purge any event listeners before overwrite innerHTML..
+            YAHOO.util.Event.purgeElement('edit', true);
             document.getElementById('edit').innerHTML = html;
             
             var btns = [{
@@ -39,6 +56,21 @@ Survey.ObjectTemplate = (function(){
                     document.getElementById('delete').value = 1;
                     this.submit();
                 }
+            }, {
+                text: "Preview",
+                handler: function(){
+                    if (type === 'answer') {
+                        alert('Sorry, preview is only supported for Sections and Questions, not Answers');
+                    }
+                    else {
+                        var msg = 'This will delete any Survey responses you have made under this ' +
+                        'user account and redirect you to the Take Survey page starting at the selected item. ' +
+                        "\n\nAre you sure you want to continue?";
+                        if (confirm(msg)) {
+                            window.location.search = 'func=jumpTo;id=' + dialog.getData().id;
+                        }
+                    }
+                }
             }];
             
             dialog = new YAHOO.widget.Dialog(type, {
@@ -49,15 +81,6 @@ Survey.ObjectTemplate = (function(){
                 buttons: btns
             });
             
-            if (type !== 'answer') {
-                btns.push({
-                    text: "Preview",
-                    handler: function(){
-                        window.location.search = 'func=jumpTo;id=' + dialog.getData().id;
-                    }
-                });
-            }
-
             dialog.callback = Survey.Comm.callback;
             dialog.render();
             
@@ -68,6 +91,8 @@ Survey.ObjectTemplate = (function(){
             if (!height) {
                 height = '300px';
             }
+
+			// N.B. SimpleEditor has a memory leak so this eats memory on every instantiation
             editor = new YAHOO.widget.SimpleEditor(textareaId, {
                 height: height,
                 width: '100%',
@@ -83,4 +108,3 @@ Survey.ObjectTemplate = (function(){
         }
     };
 })();
-