<!DOCTYPE html>
<video id="video" src="gizmo.mp4" loop></video>
<script type="text/javascript">

window.onmessage = async event => {
  const video = document.getElementById("video");
  const w = window.opener || window.parent;
  if (event.data == "play") {
    await video.play();
    w.postMessage("played", "*");
  }
}

</script>
