var browserName=navigator.appName; 
var browserVer=parseInt(navigator.appVersion); 
var plat=navigator.platform
if ((browserName=="Netscape" && browserVer>=5) || (browserName=="Microsoft Internet Explorer" && (plat != "MacPPC" && plat != "MaxIntel") && browserVer>=4)) {

} else {
  alert('Sorry, but this project contains scripts that are not supported by your browser.')
  document.location.href = 'browser.php'
}