Calling a module function name in Ajax URL
You have to create own endpoint and call post on it. For example create menu element using hook_menu:

$items['my-module-ajax-endpoint'] = array(
   'page callback' =&gt; 'my_module_ajax_callback', 
   'delivery callback' =&gt; 'ajax_deliver', 
   'access arguments' =&gt; array('access content'), 
   'type' =&gt; MENU_CALLBACK,
);


And now post to it.