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
alert('是否是Android:'+isAndroid);
alert('是否是iOS:'+isiOS);