function setRollOvers(tagName, className) {
			var allImages = document.getElementsByTagName(tagName);
			var loopLength = allImages.length;
			for(var i = 0; i < loopLength; i++) {
				if(allImages[i].className == className) {
					var src = allImages[i].getAttribute('src');
					var underSrc = src;
					var fileType = src.substring(src.lastIndexOf('.'), src.length);
					var overSrc = src.replace(fileType, '_over' + fileType);
					
					allImages[i].setAttribute('undersrc', underSrc);
					allImages[i].setAttribute('oversrc', overSrc);
					
					allImages[i].onmouseover = function() {
						this.setAttribute('src', this.getAttribute('oversrc'));
					}	
			
					allImages[i].onmouseout = function() {
						this.setAttribute('src', this.getAttribute('undersrc'));
					}
				}
			}
		}
		
		document.execCommand("BackgroundImageCache", false, true)