css overlay

gistfile1.css

#over_div {
	position:fixed;
	top:0;
	left:0;
	z-index:1987;
	width:100%;
	height:100%;
	background:#000;
	filter:alpha(opacity=70);
	opacity:0.7;
}

/*IE6 fixed*/
* html {
	background:url(*) fixed;
}
* html body {
	margin:0;
	height:100%;
}
* html #over_div {
	position: absolute;
	left: expression(documentElement.scrollLeft + documentElement.clientWidth - this.offsetWidth);
	top: expression(documentElement.scrollTop + documentElement.clientHeight - this.offsetHeight);
}