window.onload = rolloverInit;

function rolloverInit() {
	for (var i=0; i<document.links.length; i++){
		var linkObj = document.links[i];
		if (linkObj.id) {
			var imgObj = document.getElementById(linkObj.id + "Img");
			if(imgObj) {
			setupRollover(linkObj,imgObj);
			}
		}
	}
}

function setupRollover(thisLink,thisImage){
	thisLink.imgToChange = thisImage;
	thisLink.onmouseout = rollOut;
	thisLink.onmouseover = rollOver;
	
	thisLink.outImage = new Image();
	thisLink.outImage.src = thisImage.src;
	
	thisLink.overImage = new Image();
	thisLink.overImage.src = thisLink.id + "_on.jpg";
}
function rollOut() {
	this.imgToChange.src = this.outImage.src;
}

function rollOver() {
	this.imgToChange.src = this.overImage.src;
}