js判断是否ie浏览器或者浏览器版本

var Sys = {};
            var ua = navigator.userAgent.toLowerCase();
            var s;
            (s = ua.match(/rv:([d.]+)) like gecko/)) ? Sys.ie = s[1] :
                (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) {
                isIe = true;
            }