<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>