JS判断用户手机是IOS还是Android

$(function () {     var u = navigator.userAgent, app = navigator.appVersion;     var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1; //g     var isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端     if (isAndroid) {         alert("安卓机！")     }     if (isIOS) {         alert("苹果果机！")     } });