active select

Hello friends

I am trying to use active select into my module

the code is as follows

$form['_religion']=array(
'#type' => 'select', // religion select box
'#title' => t('Religion'),
'#default_value' => '',
'#options' => $religion,

);

if ($activeselect) {
$form['_religion']['#type'] ='activeselect';
$form['_religion']['#activeselect_path'] = 'customsearch/getcaste';
$form['_religion']['#activeselect_targets'] = '_caste';
$form['_religion']['#activeselect_extra'] = '';
}

and in meu hook

$items[] = array('path' => 'customsearch/getcaste',
'title' => t('active caste'),
'callback' => 'cutomsearch_getcaste',
'access' => true,
'type' => MENU_CALLBACK,);

function cutomsearch_getcaste($source, $targets, $string, $extra = NULL)
{
#if (empty($source) || empty($targets) || empty($string)) {
# exit();
# }
echo "hook ";
}

but i am not getting the desired output

any body know this issue

Regards

Sujith S