Just started using jQuery in some of our sites, but would really like to know how to NOT use it if the site visitor's browser won't support it. I've searched these forums for a while now, and re-read several of the relevant e-books I got from Sitepoint, but can't seem to find anything usable about this issue.

Specifically, I'd like to add some code to the site template that would first determine if the visitor's browser supports jQuery. If it does, continue on. If it doesn't, display this instead.

Can anyone point me in the right direction?