if (Prototype.Browser.IE) {
  Prototype.Browser.IEVersion = parseFloat(navigator.appVersion.split(';')[1].strip().split(' ')[1]);
  Prototype.Browser.IE6 =  Prototype.Browser.IEVersion == 6;
  Prototype.Browser.IE7 =  Prototype.Browser.IEVersion == 7;
}

// if (Prototype.Browser.IE6) {
//   alert('Internet Explorer 6 is not supported by AdPortal. Please upgrade your browser.'); 
// }