try.dartlang.org version 5.

dart/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;

[kasperl, 2014/01/07 07:18:43]

Do you really need this return?

[ahe, 2014/01/07 14:06:23]

No, but it makes it easier to add new cases.

+    }
+  }
+}
+
+window.addEventListener("message", onMessageReceived, false);
+
+(function () {
+function postScrollHeight() {
+  window.parent.postMessage(["scrollHeight", document.documentElement.scrollHeight], "*");

[kasperl, 2014/01/07 07:18:43]

Long line.

[ahe, 2014/01/07 14:06:23]

Done.

+}
+
+var observer = new (window.MutationObserver||window.WebKitMutationObserver||window.MozMutationObserver)(function(mutations) {

[kasperl, 2014/01/07 07:18:43]

Long line.

[ahe, 2014/01/07 14:06:23]

Done.

+  postScrollHeight()
+  window.setTimeout(postScrollHeight, 500);
+});
+
+observer.observe(
+    document.body,
+    { attributes: true,
+      childList: true,
+      characterData: true,
+      subtree: true });
+})();