paper-tab/ iron-pages

<!DOCTYPE html>

<link rel="import" href="http://kasperpeulen.github.io/PolymerElements/all.html">
<style>
  textarea {
    width: 100%;
    box-sizing: border-box;
    height: 50px;
  }
</style>
<body>
  <template is="dom-bind">
    <paper-tabs selected="{{selected}}">
      <paper-tab>HTML</paper-tab>
      <paper-tab>CSS</paper-tab>
      <paper-tab>Dart</paper-tab>
    </paper-tabs>
    <iron-pages selected="{{selected}}">
      <textarea>{{html}}</textarea>
      <textarea>p {color: tomato;}</textarea>
      <textarea></textarea>
    </iron-pages>
    <iframe srcdoc="{{iframe}}"></iframe>
    <paper-fab icon="av:play-arrow"></paper-fab>
  </template>
  <script>
    var scope = document.querySelector("template");
    scope.html = "hello";
    scope.iframe = "<html><head><style>" + scope.
  </script>
</body>