[jQuery] AJAX, sessions, and HTTP Status Codes

[jQuery] AJAX, sessions, and HTTP Status Codes

I've been thinking about using HTTP Status codes and a global ajax event to deal with session timeouts. Here's a little example:
<a href="http://erikandcolleen.com/erik/projects/jquery/ajaxlogin/">http://erikandcolleen.com/erik/projects/jquery/ajaxlogin/
</a>
Seems to work well in FF and Safari (both OSX). Is this a sound way of dealing with this? And are there any recommendations about particular response codes to use?
--Erik