Js判断是安卓Andorid还是苹果IOS系统

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