function Swap(what,which){
	what.src = what.getAttribute(which);
}

function SwapSetup()
{
var images = document.getElementsByTagName("img");
for (var i=0;i<images.length;i++)
{
	if(images[i].getAttribute("src").search("_off.") > -1) {
	images[i].altsrcimg = new Image();
	images[i].altsrcimg.src = images[i].getAttribute("src").replace("_off.", "_on.");

	images[i].onmouseover = new Function("Swap(this,'altsrc');");
	images[i].onmouseout = new Function("Swap(this,'origsrc');");

	images[i].setAttribute("origsrc", images[i].src);
	images[i].setAttribute("altsrc", images[i].altsrcimg.src);
}
}
}

var PreSwapOnload =(window.onload)? window.onload : function(){};
window.onload = function(){PreSwapOnload(); SwapSetup();}