browserName = navigator.appName;
browserVersion = parseInt(navigator.appVersion);
if (browserName == "Netscape" && browserVersion >= 3 || 
	browserName == "Microsoft Internet Explorer" && 
	browserVersion >= 4) imageSwap = "yes";
else 
	imageSwap = "no";


function Swap(image1, image2) { 
   document.images[image1].src = eval(image2 + '.src');
}