handle autoplay of <video> in A-Frame on mobile (iOS, Android) - see https://github.com/aframevr/aframe/pull/2657/files

aframe-autoplay-video-on-mobile.js

function playVideoOnClick (selector) {
  el = document.querySelector(selector);

  if (el) {
    addListener();
  } else {
    window.addEventListener('load', addListener);
  }

  function addListener () {
    if (el.paused) {
      window.addEventListener('click', handleFirstClick);
    }

    function handleFirstClick () {
      try {
        if (el.muted) {
          delete el.muted;
        }
        if (el.paused) {
          el.play();
        }
      } catch (e) {
      }
      removeHandleFirstClick();
    }

    function removeHandleFirstClick () {
      window.removeEventListener('click', handleFirstClick);
    }  
  }
}

playVideoOnClick('video');