get window size

Hi all, I've been searching for about an hour and I can't seem to find a way to pass the browser window size to flash.

I'm building a full-screen site, and I want to animate something moving from one edge to the other edge of the window.

Stage.width is always the same as the stage size in my fla.

am I missing something?

Thanks
Patrick

Never mind, aparantly I was being stupid and is was changing...