js获取浏览器类型

function add(){
            var userAgent = navigator.userAgent,   
            rMsie = /(msies|trident.*rv:)([w.]+)/,   
            rFirefox = /(firefox)/([w.]+)/,   
            rOpera = /(opera).+version/([w.]+)/,   
            rChrome = /(chrome)/([w.]+)/,   
            rSafari = /version/([w.]+).*(safari)/;  
            var browser;  
            var version;  
            var ua = userAgent.toLowerCase();  
            var stu_name;
            function uaMatch(ua) {  
                var match = rMsie.exec(ua);  
                if (match != null) {  
                    alert("IE");
                    stu_name = $("#stu_name").text().split("
"); 
                    alert(stu_name);
　　　　　　　　　　　　

var Sys = {};
var ua = navigator.userAgent.toLowerCase();
var s;
(s = ua.match(/msie ([d.]+)/)) ? Sys.ie = s[1] :
(s = ua.match(/firefox/([d.]+)/)) ? Sys.firefox = s[1] :
(s = ua.match(/chrome/([d.]+)/)) ? Sys.chrome = s[1] :
(s = ua.match(/opera.([d.]+)/)) ? Sys.opera = s[1] :
(s = ua.match(/version/([d.]+).*safari/)) ? Sys.safari = s[1] : 0;
if(Sys.ie == '8.0'){
alert("ie8");
}

                }  
                var match = rFirefox.exec(ua);  
                if (match != null) {  
                    alert("rFirefox");
                    stu_name = $("#stu_name").val().split("
"); 
                    alert(stu_name);
                }  
                var match = rOpera.exec(ua);  
                if (match != null) {  
                    alert("rOpera");
                    stu_name = $("#stu_name").val().split("
"); 
                    alert(stu_name);
                }  
                var match = rChrome.exec(ua);  
                if (match != null) {  
                    alert("rChrome");
                    stu_name = $("#stu_name").val().split("
"); 
                    alert(stu_name);
                }  
                var match = rSafari.exec(ua);
                if (match != null) {
                    alert("rSafari");
                    stu_name = $("#stu_name").val().split("
"); 
                    alert(stu_name);
                }  
                if (match != null) {
                    alert("null");
                    stu_name = $("#stu_name").val().split("
"); 
                    alert(stu_name);
                }  
            }  
            var browserMatch = uaMatch(userAgent.toLowerCase());  
}