cakephp ajax更新div不会出现

i want to create an basic web app that submits inputed data to database and also updates the div to show the data saved to database without reloading the whole page using ajax pls help me im stuck with this thnks..

here is my messages/index.ctp

<div ="success"> </div>
<?php
echo $this->Html->script('jquery', FALSE); 

echo $this->Form->create();
echo $this->Form->input('name');
echo $this->Form->input('email');
echo $this->Form->input('message');
echo $this->Js->submit('Send',array('update' => '#success'));
echo $this->Form->end();
?>

<div id="sending" style="display:none; background-color:lightgreen"> </div> 

and my MessagesController.php

<?php

class MessagesController extends AppController
{
    public $helpers = array('Js');
    public $components = array('RequestHandler');

    public function index()
    {
        if(!empty ($this->data))
        {
            if($this->Message->save($this->data))
            {
                if ($this->RequestHandler->isAjax())
                    $this->render('view', ajax);
                else
                {
                $this->Session->setFlash('Message Sent!');
                $this->redirect(array('action' => 'index'));
                }
            }
        }
    }

    public function view()
    {   
            $this->loadModel('Message');
            $data = $this->Message->find('all');
            $this->set('dbdata',$data);

    }
}

my messages/view.ctp

<table>
    <tr>
        <td>Name</td>
        <td>Email</td>
        <td>Message</td>
    </tr>
<?php foreach ($dbdata as $name) : ?>
    <tr>
        <td><?php echo $name['Message']['name'] ?> </td>
        <td><?php echo $name['Message']['email'] ?> </td>
        <td><?php echo $name['Message']['message'] ?> </td>
    </tr>

<?php endforeach; ?>