background image that moves together with the scroll bar?

[ranteo]

Hi, just wondering if it's possible for a background image that scrolls along with the scroll bar. So for example, instead of tiling the background image, or having it stretched to fit the screen, it simply remains there and scrolls down together with the scroll bar. Only vertical scrolling, and not horizontal scrolling.

Is this possible with just a mixture of css/html? Or would there be javascript involved, or it's impossible?

Many thanks for the replies, in advanced.