var preloadedImages = new Array();
var dom, nn4, ie;
dom = (document.getElementById)? true : false;
nn4 = (document.layers)? true : false;
ie = (document.all && !dom)? true : false;

function preloadImages(locationFolder) {
	if(document.images) {
			var i, args = preloadImages.arguments; 
			for(i=1; i<args.length; i++) {
				preloadedImages[args[i]]   = new Image(); 
				preloadedImages[args[i]].src   = locationFolder + args[i];
			}
	}
}
function rollOn(imageName) {
	if(document.images)
		document.images[imageName].src = preloadedImages[imageName + "_over.gif"].src;
}
function rollOff(imageName) {
	if(document.images)
		document.images[imageName].src = preloadedImages[imageName + "_normal.gif"].src;
}

function rollOver(imageName, imageUrl) {
	if(document.images)
		document.images[imageName].src = preloadedImages[imageUrl].src;
}

function rollBg(elId,cLName){
	if (dom){
	   document.getElementById(elId).className=cLName;
	}   
}