How to add javascript code in cakePHP view - cakephp

Question

I have written the following piece of code in my view page
<script type="text/javascript">
function filldetails()
{
document.getElementById('FirstName').value = "hjshjsh";
}
</script>
echo $this->Form->select('students',$student_name,array('onchange' =>filldetails()));
but i am getting an error message
call to undefined function filldetails()
How do I solve this error?

Answer 1

it should be 'onchange' => 'filldetails()'

Answer 2

Unless your project has a specific reason to avoid JS frameworks, you will avoid a lot of long-term headaches by using jQuery instead of pure Javascript.
Rewrite your view thus:
<?php
$selectDomId = $this->Form->domId('students');
$firstnameDomId = $this->Form->domId('Student.first_name');
$this->Html->scriptBlock("
jQuery(function($){
$('#{$selectDomId}').change(function(event){
$('#{$firstnameDomId}').val( $(this).val() );
});
});
",array('inline'=>false));
?>
<?php echo $this->Form->select('students',$student_name,$this->Form->domId(array(),'students'))?>
<?php echo $this->Form->input('Student.first_name')?>
The jQuery takes care of the onChange event handler, so it doesn't clutter your HTML, by hooking onto your dropdown menu's change event.
The use of Helper::domId means you don't have to worry about how CakePHP's helpers generate their id attributes, which is a net win in reliability and maintainability.