JS获取浏览器信息方法

function Browser() {

   var ua, s, i;

   this.isIE     = false;   // Internet Explorer
   this.isNS     = false;   // Netscape
   this.version = null;

   ua = navigator.userAgent;

   s = "MSIE";
   if ((i = ua.indexOf(s)) >= 0) {
     this.isIE = true;
     this.version = parseFloat(ua.substr(i + s.length));
     return;
   }

   s = "Netscape6/";
   if ((i = ua.indexOf(s)) >= 0) {
     this.isNS = true;
     this.version = parseFloat(ua.substr(i + s.length));
     return;
   }

   s = "Gecko";
   if ((i = ua.indexOf(s)) >= 0) {
     this.isNS = true;
     this.version = 6.1;
     return;
   }
}

var browser = new Browser();