CakePHP - Use jQuery to check if user is logged in thru Auth -

how can find out if user logged in cakephp thru auth component using jquery. if user logged in allow action execute if not display alert asking user log in.

<script>    $(document).ready(function(){        $(".voteup").click(function() {             // var isloggedin = ... code needed             if(isloggedin){                 var id = $(this).children("p").text();                 $(this).children("#article_thumbsup").load("/comments/voteup/"+id);             }else{                 alert('you must logged in vote on comment');             }       });   }); </script> 

assuming have commentscontroller action check_login()

public function check_login() {      // $this->auth->user() returns null or user info logged in user     if ($this->auth->user()) {          // user logged in echo success         ...      } else {          // user not logged in echo failure         ...      }  }