function prepRollovers() {
			var rollfound=0;
			var ext, imgname, noext;
			if (document.getElementsByTagName) {
				// grab all the images on a page
				for (z=0;z<document.getElementsByTagName("img").length;z++) {
					thisImg = document.getElementsByTagName("img")[z];
					// check that its got the proper class
					if (thisImg.className !=null) { // safari seems to break when these two tests are combined
						if (thisImg.className.indexOf("roll") != -1) {
							rollfound++;
							imgname = thisImg.src.toString();					// get the image name
							noext = imgname.slice(0, imgname.length-4);			// get the image name without extension
							ext = imgname.slice(imgname.length-4);				// get the extention for this image
							
							// define states, preload the image and attach the event handlers
							thisImg.out = new Image(); thisImg.out.src = thisImg.src;
							thisImg.over = new Image(); thisImg.over.src = noext + "_o"+ext;
							thisImg.parentNode.onmouseover = function () {
								this.getElementsByTagName("img")[0].src = this.getElementsByTagName("img")[0].over.src;
							};
							thisImg.parentNode.onmouseout = function () {
								this.getElementsByTagName("img")[0].src = this.getElementsByTagName("img")[0].out.src;				
							};
						}
					}
					
				}
			}
		}
		
		function rolloverother(other) {
			var theother = document.getElementById(other);
			theother.src = theother.over.src;
		}

		function rolloutother(other) {
			var theother = document.getElementById(other);
			theother.src = theother.out.src;
		};
		
		
		
					function newImage(arg) {
				if (document.images) {
					rslt = new Image();
					rslt.src = arg;
					return rslt;
				}
			}
			
			function changeImages() {
				if (document.images && (preloadFlag == true)) {
					for (var i=0; i<changeImages.arguments.length; i+=2) {
						document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
					}
				}
			}
			
			var preloadFlag = false;
			function preloadImages() {
				if (document.images) {
			imagebotan = newImage("_images/home/nav_botan_o.gif");
			imagehbotan = newImage("_images/home/home_botan.jpg");
			imagecolor = newImage("_images/home/nav_color_o.gif");
			imagehcolor = newImage("_images/home/home_color.jpg");
			imagemlab = newImage("_images/home/nav_mlab_o.gif");
			imagehmlab = newImage("_images/home/home_mlab.jpg");
			imagespider = newImage("_images/home/nav_spid_o.gif");
			imagehspider = newImage("_images/home/home_spider.jpg");
			imagecontact = newImage("_images/home/nav_contact_o.gif");

			
			
					preloadFlag = true;
				}
			}