* Update on 2010-08-08: Please refer to Ajax implementation on CakePHP @ 3 for Ajax form in CakePHP.

An ajax call which only replaces the text may not be what u want to do. Here is the sample code of an ajax form in CakePHP.

Ajax Form

1. Included the necessary helpers and component in the Controller
2. Create a before-submission-form function to render the initial form view
3. Create a after-submission-form to render the web content after the ajax call
4. Here is an example controller

<?php
Class AjaxController extends AppController {
   var $name = 'Ajax';
   var $helpers = array('Form','Html','Javascript', 'Ajax');
   var $components = array('RequestHandler');

   function beforeAjaxAction() {
      // do sth before rendering the before_ajax_action.ctp
   }

   function afterAjaxAction () {
      // get the $this->data to collect the form information
      // save the object to database
      // render the after_ajax_call.ctp
      $this->render('/elements/layout/after_ajax_call');
   }
}

5. Prepare the before_ajax_action.ctp

• model is the database model which will saves the form data
• ajaxDiv is the div which will be updated after the ajax call
• form_id is the form id for javascript
• url refers to the location of the beforeVoteAjax function and afterVoteAjax function

<div id='ajaxDiv'>
   // create the form
   <?php
      echo $ajax->form(array('type' => 'post',
                             'options' => array('model' => 'model',
                                                'update' => 'ajaxDiv',
                                                'id' => 'form_id',
                                                'url' => array('controller' => 'AjaxController',
                                                               'action' => 'beforeVoteAjax'))));
   ?>
   <?php echo $form->input(...); ?>
   <?php echo $form->input(...); ?>
   <?php echo $form->input(...); ?>
   <?php echo $ajax->submit('Submit', array('url' => '/ajax_controller/afterAjaxAction', 'update'=>'ajaxDiv', 'before' => <OPTIONAL - Ajax callback option for javascript>)); ?>
   <?php echo $form->end(); ?>
</div>

6. Prepare the content after the ajax call – ~/elements/layout/after_ajax_call.ctp

<?php echo 'Your ajax call works!' ?>

7. Test your ajax form

8. Done! =)