css popup

I need a simple css pop-up with faded background. Javascript is only allowed for triggering the box on/off and getting the window height/width or some IE issues. Must be compatible with FF/IE6/IE7/Safari. Prefer someone that have done such thing already. If you want i can give you a sample of what i'm looking for (but working only in FF and not fully). The fading should be instant - not like lightbox - an animation.. The pop-up should be inner element i.e. div, iframe and such.. The cheapest and fastest offer wins