Trap when a window is closed

[dmjpro]

When I did VC++ then I learned that the window onclose function can be overidden.
But is it possible in js to trap when I close a window.
I need the immediate help?

[acoder]

You can use

window.onbeforeunload = ...

I'm not sure how well it is supported.

[dmjpro]

I want to override the default behaviour of window close.
I want to customize the window close event.
I want to stop window to close when user intends to close it.
I want some clean up operations before closing the window.

[acoder]

You can use:

window.onbeforeunload=function() {...

or call your function. You can code your function to ask for confirmation, etc.