Pop Up A Window When Logged In Successfully...

I have a client who needs a pop-up-window with the url of his chat to load once and only once during the login. I thought this would be easy and it seems to be having problems. Maybe somebody can help?

function popupchat() {

?>
<SCRIPT LANGUAGE="javascript">
<!--
window.open ('http://languageconnectsus.gixawchat.com/')
-->
</SCRIPT>
<?php

}

add_action('wp_login ', 'popupchat');

Added that as a file in mu-plugins and it doesn't work. Any suggestions?