window.onload = rolloverInit;
/*-- this function initiates the rollover --*/
function rolloverInit() {
    for (var i=0; i<document.images.length; i++) {
        if (document.images[i].parentNode.id == "nav") {
            setupRollover(document.images[i]);
		}
	}
}
/*-- this function calls the onmouseout state of the rollover based on the image source --*/
function setupRollover(thisImage) {
	/* alert (thisImage.id); */
    thisImage.outImage = new Image();
    thisImage.outImage.src = thisImage.src;
    thisImage.onmouseout = rollOut;
    /*-- this performs the rollover based on the image src plus the variable "_roll.gif" on the end of it --*/
    thisImage.overImage = new Image();
    thisImage.overImage.src = "images/navigation/" + thisImage.id + "_roll.gif";
    thisImage.onmouseover = rollOver;	
}
/*-- these functions perform the setupRollover function --*/
function rollOver() {
    this.src = this.overImage.src;
}

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