never use `for (var i in array)`

because javascript is terrible

IPython/html/static/notebook/js/celltoolbar.js

@@ -234,7 +234,7 b' var IPython = (function (IPython) {'
      *
      */
     CellToolbar.rebuild_all = function(){
-        for(var i in CellToolbar._instances){
+        for(var i=0; i < CellToolbar._instances.length; i++){
             CellToolbar._instances[i].rebuild();
         }
     };
@@ -252,8 +252,8 b' var IPython = (function (IPython) {'
         var callbacks = CellToolbar._callback_dict;
         var preset = CellToolbar._ui_controls_list;
         // Yes we iterate on the class variable, not the instance one.
-        for (var index in preset) {
-            var key = preset[index];
+        for (var i=0; i < preset.length; i++) {
+            var key = preset[i];
             var callback = callbacks[key];
             if (!callback) continue;
             
@@ -380,10 +380,10 b' var IPython = (function (IPython) {'
             var button_container = $(div);
             var lbl = $("<label/>").append($('<span/>').text(label));
             var select = $('<select/>').addClass('ui-widget ui-widget-content');
-            for(var itemn in list_list){
+            for(var i=0; i < list_list.length; i++){
                 var opt = $('<option/>')
-                    .attr('value', list_list[itemn][1])
-                    .text(list_list[itemn][0]);
+                    .attr('value', list_list[i][1])
+                    .text(list_list[i][0]);
                 select.append(opt);
             }
             select.val(getter(cell));

IPython/html/static/notebook/js/completer.js

@@ -13,15 +13,16 b' var IPython = (function (IPython) {'
             str = '%'+str ;
         }
         return str;
-    }
+    };
 
     function _existing_completion(item, completion_array){
-        for( var c in completion_array ) {
-            if(completion_array[c].trim().substr(-item.length) == item)
-            { return true; }
+        for( var i=0; i < completion_array.length; i++) {
+            if (completion_array[i].trim().substr(-item.length) == item) {
+                return true;
+            }
         }
-       return false;
-    }
+        return false;
+    };
 
     // what is the common start of all completions
     function shared_start(B, drop_prct) {
@@ -164,9 +165,9 b' var IPython = (function (IPython) {'
         var filtered_results = [];
         //remove results from context completion
         //that are already in kernel completion
-        for (var elm in results) {
-            if (!_existing_completion(results[elm].str, matches)) {
-                filtered_results.push(results[elm]);
+        for (var i=0; i < results.length; i++) {
+            if (!_existing_completion(results[i].str, matches)) {
+                filtered_results.push(results[i]);
             }
         }
 

IPython/html/static/notebook/js/outputarea.js

@@ -503,8 +503,8 b' var IPython = (function (IPython) {'
     };
     
     OutputArea.prototype.append_mime_type = function (json, element, handle_inserted) {
-        for (var type_i in OutputArea.display_order) {
-            var type = OutputArea.display_order[type_i];
+        for (var i=0; i < OutputArea.display_order.length; i++) {
+            var type = OutputArea.display_order[i];
             var append = OutputArea.append_map[type];
             if ((json[type] !== undefined) && append) {
                 var value = json[type];

IPython/html/static/notebook/js/toolbar.js

@@ -65,20 +65,22 b' var IPython = (function (IPython) {'
      */
     ToolBar.prototype.add_buttons_group = function (list, group_id) {
         var btn_group = $('<div/>').addClass("btn-group");
-        if( group_id != undefined ) {
+        if( group_id !== undefined ) {
             btn_group.attr('id',group_id);
         }
-        for(var el in list) {
+        var el;
+        for(var i=0; i < list.length; i++) {
+            el = list[i];
             var button  = $('<button/>')
                 .addClass('btn')
-                .attr("title", list[el].label)
+                .attr("title", el.label)
                 .append(
-                    $("<i/>").addClass(list[el].icon)
+                    $("<i/>").addClass(el.icon)
                 );
-            var id = list[el].id;
-            if( id != undefined )
+            var id = el.id;
+            if( id !== undefined )
                 button.attr('id',id);
-            var fun = list[el].callback;
+            var fun = el.callback;
             button.click(fun);
             btn_group.append(button);
         }
@@ -96,7 +98,7 b' var IPython = (function (IPython) {'
      */
     ToolBar.prototype.toggle = function () {
         this.element.toggle();
-        if (IPython.layout_manager != undefined) {
+        if (IPython.layout_manager !== undefined) {
             IPython.layout_manager.do_resize();
         }
     };