site/try/iframe.js

// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

function dartPrint(msg) {
  window.parent.postMessage(String(msg), "*");
}

window.onerror = function (message, url, lineNumber) {
  window.parent.postMessage(
      ["error", {message: message, url: url, lineNumber: lineNumber}], "*");
};

function onMessageReceived(event) {
  var data = event.data;
  if (data instanceof Array) {
    if (data.length == 2 && data[0] == 'source') {
      var script = document.createElement('script');
      script.innerHTML = data[1];
      script.type = 'application/javascript';
      document.head.appendChild(script);
      return;
    }
  }
}

window.addEventListener("message", onMessageReceived, false);

(function () {
function postScrollHeight() {
  window.parent.postMessage(["scrollHeight", document.documentElement.scrollHeight], "*");
}

var observer = new (window.MutationObserver||window.WebKitMutationObserver||window.MozMutationObserver)(function(mutations) {
  postScrollHeight()
  window.setTimeout(postScrollHeight, 500);
});

observer.observe(
    document.body,
    { attributes: true,
      childList: true,
      characterData: true,
      subtree: true });
})();