Analyzing the mobile device is IOS / Android system

var u = navigator.userAgent;
var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Adr') > -1; //android终端
var isiOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端
alert('是否是Android：'+isAndroid);
alert('是否是iOS：'+isiOS);