This script used to be on my main page and was so requested for, that I set up an example of it for you viewers to have. As you guessed, this script checks to see if the viewer's browser is javascript compatible or not. If not, it gives a message for them to download a later browser.
The source..


<script language="Javascript">
<!--
// please keep these lines on when you copy the source
// made by: Nicolas - http://www.javascript-page.com

document.write("<b><font color='#000099'>You have a "
+"javascript compatible browser.</b></font>");

//-->
</script>
<noscript>
<b><font color="#000099">Sorry, you do not have a javascript compatible browser.  
I recommend you get a javascript compatible browser at 
<a href="http://www.netscape.com">Netscape's Homepage</a>.</font></b>
</noscript>