Can you detect iPhone vs Android with AMP?

Let's say I have an APPLE PODCASTS button and a GOOGLE PODCASTS button, and I'd like to show:

APPLE PODCASTS to iPhone users
GOOGLE PODCASTS to Android users
BOTH to desktop users

I'm currently achieving this with AMP by using <amp-list> and calling a dynamically-produced JSON file. That works fine; but I'm wondering if there's a native way that would remove the requirement for these three files - <amp-list>, <amp-mustache> and the dynamic JSON file - to be loaded.

Solution

You can detect the UA string in an amp-script and then update the buttons accordingly:

<amp-script layout="fixed-height" height="50"
  script="user-agent-script">
  <button id="android" hidden>Android</button>
  <button id="iOS" hidden>iOS</button>
</amp-script>

<script id="user-agent-script"
  type="text/plain"
  target="amp-script">

  function getMobileOS() {
    const userAgent = navigator.userAgent;
    if (/android/i.test(userAgent)) {
      return "android";
    }
    // iOS detection from: http://stackoverflow.com/a/9039885/177710
    if (/iPad|iPhone|iPod/.test(userAgent) && !window.MSStream) {
      return "ios";
    }

    return "other";
  }

  const androidButton = document.querySelector('#android');
  const iosButton = document.querySelector('#ios');

  const os = getMobileOS();
  if (os === 'android') {
    androidButton.removeAttribute('hidden');
  } else if (os === 'ios') {
    ios.removeAttribute('hidden');
  } else {
    androidButton.removeAttribute('hidden');
    ios.removeAttribute('hidden');
  }

</script>

Sample: https://amp.dev/documentation/examples/components/amp-script/#detecting-android-vs-ios-in-amp