Background stretch tag in HTML

I'd like to know how to have a background scale to fit the users screen resolution so my image doens't get cut off or repeated....the image itself is 1024x768 which seems to be a fairly popular resolution, but when users of other resolutions visit, how do i accomplish this? :confused:

You could use JavaScript to detect the users resolution and output the appropriate image.

document.write('<img src="images/mypicture1024.jpg">');

...something like that.