Is there a way to cover the whole window area within a web site, using Javascript/jQuery? -

Yes, otherwise I'm starting to make my cover in CSS, so it covers 770px or 990 px etc.

This should be like scaling after the size / resolution of windows. Is there any way to adjust it for each computer using JavaScript / jQuery?

Using CSS:

 . Overlay {status: complete; Top: 0 pixels; Bottom: 0 pixels; Left: 0 pixels; Correct: 0 pixels; Width: 100%; Height: 100%; }