Yii CActiveForm: почему не работает clientValidation вкупе с CHtml::ajaxSubmitButton?

$checkOrderForm = $this->beginWidget('CActiveForm', array(
    'id' => 'check-order-form',
    'stateful' => true,
    'enableClientValidation' => true,
    'clientOptions' => array(
        'hideErrorMessage' => TRUE,
        'validateOnSubmit' => TRUE,
        'validateOnChange' => FALSE,
        'validateOnType' => TRUE,
        'errorCssClass' => 'has-error',
        'afterValidate' => 'js:ajaxCheckOrder',
    )
));

function ajaxCheckOrder(form, data, hasError) {

    if (!hasError) {
        $.ajax({
            type: "POST",
            //url: "",
            data: $("#check-order-form").serialize(),
            success: function(data) {
                $("#checkOrderResult").slideUp(400, function() {
                    $(this).html(data);
                }).slideDown();
            }

        });
        return false;
    }
}