<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Dart Draggable (div) Element</title>
  </head>
  <body>

  <div id="dragMe" style="width: 200px; height: 200px; background: yellow;">Drag Me</div>

  <script type='text/javascript'>
  var script = document.createElement('script');
  if (navigator.userAgent.indexOf('(Dart)') === -1) {
    // Browser doesn't support Dart
    script.setAttribute("type","text/javascript");
    script.setAttribute("src", "app.js");
  } else {
    script.setAttribute("type","application/dart");
    script.setAttribute("src", "app.dart");
  }
  document.getElementsByTagName("head")[0].appendChild(script);
  </script>
  </body>
</html>