Navigator对象中包含了浏览器相关的信息，其中userAgent,返回的是客户端发送服务端的user-agent头部的值
function getBrowserTypeAndVersion() {
var sys = {},
content = navigator.userAgent.toLowerCase(),
r;
(r = content.match(/rv:([\d.]+)\) like gecko/)) ? sys.ie = s[1]:
(r = content.match(/msie ([\d\.]+)/)) ? sys.ie = s[1] :
(r = content.match(/edge\/([\d\.]+)/)) ? sys.edge = s[1] :
(r = content.match(/firefox\/([\d\.]+)/)) ? sys.firefox = s[1] :
(r = content.match(/(?:opera|opr).([\d\.]+)/)) ? sys.opera = s[1] :
(r = content.match(/chrome\/([\d\.]+)/)) ? sys.chrome = s[1] :
(r = content.match(/version\/([\d\.]+).*safari/)) ? sys.safari = s[1] : 0;
// 根据关系进行判断
if (sys.ie) return ('IE: ' + sys.ie)
if (sys.edge) return ('EDGE: ' + sys.edge)
if (sys.firefox) return ('Firefox: ' + sys.firefox)
if (sys.chrome) return ('Chrome: ' + sys.chrome)
if (sys.opera) return ('Opera: ' + sys.opera)
if (sys.safari) return ('Safari: ' + sys.safari)
return 'Unkonwn'
}
