Yii - Using Ajax Validation

I'm trying to enable ajax validation in a form, I've added the right parameters to the form, but it's not working, here's my code:

<?php $form=$this->beginWidget('CActiveForm', array(
    'id'=>'user-form',
    'enableAjaxValidation'=>true,
    'htmlOptions' => array(
            'enctype' => 'multipart/form-data',
            'enableClientValidation'=>true
    ),
)); ?>

Please advice.