[jQuery] Re: Intercept "Back" button click on browser

[Dave Methvin]

The history plugins can handle that situation, you just have to update
the hash in the URL to keep track of the state of the page. It takes
some study to understand how it works, but believe me you will want to
use it. There is no way to "trap" the back button, the only other
thing you can do is set an onunload handler and that is really a last-
ditch thing to prevent the user losing data.