Topic awaiting preservation: Prompting before closing a window?

On the online game I am working on, I would like to prompt a user with 'are you sure you wish to close this window?' (yes/no) when they attempt to close the window. However, cant seem to figure out how to caputre the closing window event

there is the unLoad, however that gets called on a page reload or simply moving to the next page (which I dont want to do..). Anyone know how I would go about doing this?

You can't cancel the closing of a window; if you could, people would use it malisciously. Speaking of which, I need to learn how to spell malisciously sometime.

*ponders*

I guess my only option then would be to popup a chromless window then I suppose. *grumble*

There's always the "don't override the user's interface" option...