I am new to PHP and CakePHP. I m trying to call Ajax on changing drop down item. I have done it for a link as below code

```
echo $this->Html->link('TestLink', array('controller'=>'Tutors','action'=>'getData',$iid), array('class'=>'js-ajax')); 

```

but unable to apply on drop down. I have used the code for drop down as below

```
echo $this->Form->input('My City', array('empty'=>'Select City','options' => $cities));

```

here, where to put code to call ajax.
Please help.