browser_name = navigator.appName;
browser_version = parseFloat(navigator.appVersion);
if (browser_name == "Netscape" && browser_version >= 3.0)
{ roll = 'true'; }
else if (browser_name == "Microsoft Internet Explorer" &&
browser_version >= 3.0) { roll = 'true'; }
else { roll = 'false'; }

function change(img,ref) { if (roll == 'true') {
document.images[img].src = ref; } }