Is this the right forum? (Trying to style my chat popup window).

I have inherited this project from another developer.  I thought it would be much easier to apply css to this, or least find out how to do so.  I even tried inserted a JQuery CSS statement into the window.open

<a  class="live-chat-link" onclick="launchChat();return false;">Live Chat</a>

<script>

    function launchChat(){

        window.open("/chat", "_blank", "width=410, height=400");

        $(.LPMcontainer).css("border", "none");

  $(.LPMoverlay).css("border", "none");

  )}

</script>