判断浏览器内核JS代码

<script type="text/javascript">
                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;
                //以下进行测试
                if (Sys.ie) document.write('IE: ' + Sys.ie);
                if (Sys.firefox) document.write('Firefox: ' + Sys.firefox);
                if (Sys.chrome) document.write('Chrome: ' + Sys.chrome);
                if (Sys.opera) document.write('Opera: ' + Sys.opera);
                if (Sys.safari) document.write('Safari: ' + Sys.safari);
 </script>