CakePHP configuration of the dependent AJAX drop-down list


I have done a lot of research, tried to apply a few different examples but it seems that nothing really works.

So I have the following 3 models: Customers, Projects and Events. Customers have many Projects and Projects have many Events.

While creating an Event, I would like a user to select a Customer from a dropdown list and then the user should be provided with a list of Projects that belong to the selected Customer. The closest I have got to is the following. I do not have experience with AJAX, so that really is a hard nut to brake.

Action in the Porject's controller:

    public function getbycustomer(){

    $customer_id = $this->request->data['Event']['customer_id'];

    $projects = $this->Project->find('list', array('conditions'=>array('Project.customer_id' => $customer_id), 'recursive' => -1));

    $this->set('projects', $projects);
    $this->layout = 'ajax';

View for this action is the following:

    <?php foreach ($projects as $key => $value): ?>
<option value="<?php echo $key; ?>"><?php echo $value; ?></option>
<?php endforeach; ?>

And here is the snippets from the view for adding an event:

    echo $this->Form->input('customer_id');
        echo $this->Form->input('project_id'); 

//form continues and at the end of a page there is the AJAX call

        ), array(
        'async' => true,
        'method' => 'post',
        'data'=> $this->Js->serializeForm(array(
            'isForm' => true,
            'inline' => true

Any help is much much appreciated as I do not even know the proper way for debugging it, so I could provide more valuable information.

go to this. this helped me to do the dependent drop down list. it provies a details step by step process.