function doRollover() {
	$(".rollover").hover(
		function() {
			imgOff = $(this).attr("src");
			imgOn = imgOff.replace("Off.gif", "On.gif");
			$(this).attr({ src: imgOn });
		},
		function() {
			$(this).attr({ src: imgOff });
		}
	)
	
	$(".rollover").each(function() {
		imgOff = $(this).attr("src");
		imgOn = imgOff.replace("Off.gif", "On.gif");
		img = new Image();
		img.src = imgOn;
	});
}

<!--
function MM_openBrWindow(theURL,winName,features) { //v2.0
 window.open(theURL,winName,features);
}
//-->