php - Symfony 1.4 & ajax parameter "null" -

i'm trying use ajax,but cant reach variables in php.

on symfony page have :

$.ajax({    type: "post",    url: "agenda/data",    data: { title : title} }); 

and in action.class.php => executedata function try parameter : $title = $request->getparameter('title'); return null . why?

how can javascript variables action.class.php (i want insert them in db, , don't want null parameter lol)?