I don't have a clue what I'm doing but I got it to work! Don't you love it when that happens?
Here's what I did. I borrowed some code from the top of the faq_english.php file, since the "Who's Online" updates when users go to THAT file......
So, my new "chatpopup.php" looks like this:
[:"blue"]
<?
// Require the library
require ("./main.inc.php");
$html = new html;
$html -> send_header("Updater",$Cat,0,0,0,0,"");
echo "
<script language="javascript" type="text/javascript">
window.blur();</script>
<meta http-equiv="refresh" content="550">
<div align="center"><b><font face="ariel" size="2">
Please leave this window open while you
are in the Chat Room.</b>
</font></b></div>";
?>
[/]
My "jchat.tpl" inludes this line, to call-up the "chatpopup.php": [:"blue"]
<script language="javascript" type="text/javascript"> window.open('http://www.mysite.com/threads/chatpopup.php?Cat=&Username=$Username&Usernumber=$Usernumber',
'chatpopup','width=800,height=300,top=000,left=000,
screenX=1,screenY=1,scrollbars=yes,resizable=yes');
</script>
[/]
The one snaglette is my chatpopup.php brings up my header, which is an unecessary bandwidth-user, especially given that it refreshes every (nearly) 10 minutes. And of course it also makes the chatpopup window unecessarily wide. So I'd love to find a way around THAT.