yii?删除按钮问题

Views->index.php:  'delete' => array        (             'label'=>'Delete Record',              'imageUrl'=>Yii::app()->request->baseUrl.'/images/list_del.gif',               url'=>'Yii::app()->createUrl("series/delete", array("id"=>$data->id,"menu"=>Yii::app()->controller->curmenu))',           ),Controller: public function actionDelete($id)    {        if($id==4) {            $model = $this->loadModel($id);            $model->delete();            if (!isset($_GET['ajax']))                $this->redirect(isset($_POST['returnUrl']) ? $_POST['returnUrl'] : array('admin'));        }else{   /*echo("<script>alert(1);</script>");*/  //不会弹出错误信息框?//当id不等于4时,弹出一个错误信息  (  这部分未实现)        }    }