Yii Delete Records With Multi Check Box

Yii::app()->clientScript->registerScript('deleteall','
$("#deleteall").click(function(){
        var checked=$("#casecategory-grid").yiiGridView("getChecked","casecategory-grid_c0");
        var count=checked.length;
        if(count>0 && confirm("Do you want to delete these "+count+" item(s)"))
        {
                $.ajax({
                        data:{checked:checked},
                        url:"'.CHtml::normalizeUrl(array('Casecategory/removeall')).'",
                        success:function(data){$("#casecategory-grid").yiiGridView("update",{});},              
                });
        }
        });
');



$this->widget('zii.widgets.grid.CGridView', array(
 'id'=>'casecategory-grid',
 'dataProvider'=>$model->search(),
 'filter'=>$model,
 'columns'=>array(
 
                array(
                'class'=>'CCheckBoxColumn',  //CHECKBOX COLUMN ADDED.
                'selectableRows'=>2,         //MULTIPLE ROWS CAN BE SELECTED.
                ),

  'name',

        array(
            'name'=>'parent',
            'type'=>'raw',
            'value'=>'$data->getparent ? $data->getparent->name : " No Parent"',
       //     'filter' => CHtml::listData(User::model()->findAll(), 'id', 'fullname'),
        ),
  array(
   'class'=>'CButtonColumn',
  ),
 ),
));


echo CHtml::button("Remove Selected Items",array("id"=>"deleteall"));


// Controller
public function actionRemoveall()
{   if(Yii::app()->request->getIsAjaxRequest())
        {
                $checkedIDs=$_GET['checked'];
                foreach($checkedIDs as $id)
                        Casecategory::model()->deleteByPk($id);
        }
}