Trigger `play()` based on a message from a parent page.

gistfile1.js

videojs.plugin('iframePlay', function(options) {
  var player = this;
  options = options || {};
  window.addEventListener('message', function(event) {
    if (!options.origin || options.origin === event.origin && event.data === 'play') {
      player.play();
    }
  });
});