need help optimizing internal ajax callbacks

ive got a node_alter function in my custom node type, and need to populate some textboxes with calculated values depending on another fields values...simple, but its taking the ajax callback 5 seconds to update the field, even if i only target the element...so i installed js module, but im not seeing a difference...here is my code in the module:

function match_js() {
   return array(
     'drupal_get_form' => array(
       'callback' => 'match_courts_callback',
       'bootstrap' => DRUPAL_BOOTSTRAP_DATABASE,
      ),
   );
 }

i have no idea if this is the correct way to call the js module into play...can someone help? the url for the ajax is the internal system/ajax

thanks!