浏览器判断

<script type="text/javascript"> 
if(navigator.appName == "Microsoft Internet Explorer" && navigator.appVersion.match(/7./i)=="7.") 
{ 
  alert("IE 7.0"); 
} 
else if(navigator.appName == "Microsoft Internet Explorer" && navigator.appVersion.match(/8./i)=="8.") 
{ 
  alert("IE 8.0"); 
} 
else if(navigator.appName == "Microsoft Internet Explorer" && navigator.appVersion.match(/9./i)=="9.") 
{ 
  alert("IE 9.0"); 
} 
else if(navigator.appName == "Microsoft Internet Explorer") 
{ 
  alert("IE 6.0"); 
} 
</script>