OnBeforeUnload Event WORKS IN FIREFOX, TOO!!!

A page on the MSDN is erroneously spreading the notion that onBeforeUnload is supported only by IE.

onbeforeunload Event (BODY, FRAMESET, window)

That is totally false. FireFox has supported onBeforeUnload since version 1.7. The reason there is beef about this event is that it is not a part of either the W3C spec or the ECMA spec. However, it has taken on wide support because it provides necessary functionality. It is used mainly to keep a user from navigating away from a page where they have unsaved input (more for web apps than pages).

So by all means use onBeforeUnload if you need that kind of functionality as it is likely to be adopted into some standard due to it's far reaching use (even Google does it). Just be sure that you script something for onUnload for the Opera users.