Bootstrap模态表单替换为JSON

Question

I've got a problem with replacing registration form when some errors occur. My form is rendered in bootstrap modal and validated using Zend controller action. When I submit not valid form it should be replaced with the same form but with errors displayed. Below is my code.

Zend action:

public function registerAction(){

        $result = array("success" => true);
        $view = new Zend_View();
        $form = new Application_Form_DesktopUser_Register();
        $view->form = $form;

        $result["form"] = $form;
        if($this->_request->isPost()){
            if($form->isValid($this->_request->getPost())){

                    //Some code
                }

            else{
                $result["success"] = false;
            }
        }
        exit;
        $this->_helper->json($result);
    }

My JavaScript code:

<script type="text/javascript">
$(document).ready(function(){

    $('body').on('submit', '#registerForm', function(event){


        event.preventDefault();

        $('.alert').remove();


        $.ajax({
            type: "POST",
            url: $('#registerForm').attr('action'),
            data: JSON.stringify($('#registerForm').serializeArray()),
            dataType: 'json',
            contentType: 'application/json',
            success: function(data){   
                if(data["success"] == false){
                    $('#registerForm').html('error').show();
                }
                else{

                }
            },
            error: function(data){                   
                $('.formdiv').html($(data.form).html());
            }
        });
        return false;
    });
});