How to use Js->submit() in CakePHP?

Question

Im trying to create a simple Ajax form for a message board in a CakePHP application, but I can't for the life of me figure out how to properly use the Js->submit() function to submit a form via Ajax.

Heres the form code within my view:

<?php

 echo $this->Form->create('Message',array(
  'type' => 'post', 
  'action' => 'add',
  'onSubmit' => 'return false;'
 ));

 echo $this->Form->input('name', array('label' => 'From:'));
 echo $this->Form->input('text', array('label' => 'Message:'));

 echo $this->Js->submit('Post Your Message', array(
  'action' => 'add',
  'update' => '#message_board'
 ));

 echo $this->Form->end();

?>

<div id="message_board">
    ...
</div>

And here is the controller action:

function add() {
 $this->autoRender = false; 
 if($this->RequestHandler->isAjax()) {
     $this->layout = 'ajax'; //THIS LINE NEWLY ADDED
     if(!empty($this->data)) {
         if($this->Message->save($this->data)) {
             $this->Session->setFlash('Your Message has been posted');
         }
     }
 }
}

Oddly, what happens when I submit the form is an exact copy of the form and its containing div is duplicated INSIDE the message_board div. Weird.

Obviously I'm missing something (or several things). If anyone has any idea, or else knows a good source of information on how to use it, it would be much appreciated.

Thanks.

UPDATE: I tried adding the new line $this->layout = 'ajax'; to the controller (see above), but it had no effect. Here is the jquery output by CakePHP, incase that might tell somebody whats going on.

$(document).ready(function () {
    $("#submit-707957402").bind("click", function (event) {
        $.ajax({
            action:"add", 
            data:$("#submit-707957402").closest("form").serialize(), 
            dataType:"html", 
            success:function (data, textStatus) {
                $("#message_board").html(data);
            }, 
            type:"post", 
            url:"\/messages"
        });
        return false;
    });
});

Answer 1

What happens is that it loads the default layout. You'll have to change the layout to ajax with the following line:

$this->layout = 'ajax';

You insert that line inside your isAjax() condition.

Also your options array has the wrong format. The action key should be inside the url key.

$this->Js->submit('Post Your Message', array(
        'url' => array(
            'action' => 'add'
        ),
        'update' => '#message_board'
    )
);