JS判断浏览器类型

case 1
function CheckBrowser(){
    var cb = "Unknown";
    if(window.ActiveXObject){
        cb = "IE";
    }else if(navigator.userAgent.toLowerCase().indexOf("firefox") != -1){
        cb = "Firefox";
    }else if((typeof document.implementation != "undefined") && (typeof document.implementation.createDocument != "undefined") && (typeof HTMLDocument != "undefined")){
        cb = "Mozilla";
    }else if(navigator.userAgent.toLowerCase().indexOf("opera") != -1){
        cb = "Opera";
    }
    return cb;
}

case 2;[align=left][/align]
  if (window.XMLHttpRequest) { //Mozilla, Safari,...IE7 
  alert('Mozilla, Safari,...IE7 ');
      if(!window.ActiveXObject)// Mozilla, Safari,...
      {         
         alert('Mozilla, Safari');
      } 
      else
      {
          alert('IE7');
      }
      
      
  }
  else
  {
       alert('IE6');
  }