window.addEventListener('message', function (event) {
  if (event.data == "FrameHeight") {
    var body = document.body, html = document.documentElement;
    var height = Math.max(body.scrollHeight, body.offsetHeight, html.clientHeight, html.scrollHeight, html.offsetHeight);
    event.source.postMessage({ "FrameHeight": height }, "*");
  }
});