if (MENU.msieFixedPositionBug) {
MSIE can't do fixed position, so use a full-sized background
and an onresize handler to update it (stupid, but necessary)
div.width = div.height = 0; this.Resize();
attachEvent("onresize",this.Resize);
} else {
otherwise, use a fixed position DIV to cover the viewport
bg.style.position = "fixed";
}
...