Simplified beforeFilter and afterFilter events

Removed `form` as a parameter to the events since it can be retrieved using `$grid.find('form.gridview-filter-form')`.

framework/assets/yii.gridView.js

@@ -33,10 +33,9 @@
         /**
          * beforeFilter event is triggered before filtering the grid.
          * The signature of the event handler should be:
-         *     function (event, form)
+         *     function (event)
          * where
          *  - event: an Event object.
-         *  - form: is the grid filter form that will be submitted
          *
          * If the handler returns a boolean false, it will stop filter form submission after this event. And as
          * a result, afterFilter event will not be triggered.
@@ -45,10 +44,9 @@
         /**
          * afterFilter event is triggered after filtering the grid and filtered results are fetched.
          * The signature of the event handler should be:
-         *     function (event, form)
+         *     function (event)
          * where
          *  - event: an Event object.
-         *  - form: is the grid filter form that will be submitted
          */
         afterFilter: 'afterFilter.yiiGridView'
     };
@@ -109,7 +107,7 @@
             
             // triggers `beforeFilter` grid event with the filter form as a parameter
             event = $.Event(gridEvents.beforeFilter);
-            $grid.trigger(event, [$form]);
+            $grid.trigger(event);
             if (event.result === false) {
                 return;
             }
@@ -118,7 +116,7 @@
             
             // triggers `afterFilter` grid event with the filter form as a parameter
             event = $.Event(gridEvents.afterFilter);
-            $grid.trigger(event, [$form]);
+            $grid.trigger(event);
         },
 
         setSelectionColumn: function (options) {