a question about module popups

hi,everyone, I want to use 'popups' module to display a dialog in my module
http://drupal.org/project/popups

but it always say

'Fatal error: Call to undefined function message() in D:\wwwroot\sites\all\modules\mymodule\mymodule.module on line 126'

the below is my code

function mymodule_form_submit ($form_id, &$form_state) {
Drupal.popups.message("faint");
}

anybody can help me,thanks a lot.