h5判断设备是ios还是android

var u = navigator.userAgent, app = navigator.appVersion;
var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1; //android终端或者uc浏览器
var isiOS = !!u.match(/(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端