window.onload = rolloverInit;

function rolloverInit(){
	for (var i=0; i<document.images.length; i++){
		var imgObj = document.images[i];
		if (imgObj.id){			
			if (document.images[i].parentNode.tagName == "A"){
				setupRollover(document.images[i]);
			}
		}
	}
}

function setupRollover(esteImage){
	esteImage.outImage = new Image();
	esteImage.outImage.src = esteImage.src;
	esteImage.onmouseout = rollOut;
	
	esteImage.overImage = new Image();
	esteImage.overImage.src = "images/" + esteImage.id + "-over.jpg";
	esteImage.onmouseover = rollOver;
	
	esteImage.parentNode.childImg = esteImage;
	esteImage.parentNode.onblur = rollOutChild;
	esteImage.parentNode.onfocus = rollOverChild;
}

function rollOut(){
	this.src = this.outImage.src;
}

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

function rollOutChild(){
	this.childImg.src = this.childImg.outImage.src;
}

function rollOverChild(){
	this.childImg.src = this.childImg.overImage.src;
}