Javascript: closing opener window?

I’m not using frames.
My main window creates a window when the user submits a form. the pop-up window’s form action can only function as long as the main opener window’s state is active (opened). I want to be able to close the pop-up window stillopened if the main window is closed firet!?

So, basically, if the main window is closed before the pop-up window is closed, kill the pop-up window.

Any ideas on how I could achieve this!?

Thanks!
Mike