title: Why this angularjs example doesn't work on plunker?
body: <p>In this angular document: <a href="http://docs.angularjs.org/guide/concepts" rel="noreferrer">http://docs.angularjs.org/guide/concepts</a>, there is an example about <code>Directives</code>.</p>
  <blockquote>
  <h2>Directives</h2>
  <p>A directive is a behavior or DOM transformation which is triggered by the presence of a custom attribute, element name, or a class name. A directive allows you to extend the HTML vocabulary in a declarative fashion. Following is an example which enables data-binding for the contenteditable in HTML.</p>
  </blockquote>
  <p>It provides two live demo, one for plunker, another for jsfiddle.</p>
  <ul>
  <li>plunker: <a href="http://plnkr.co/edit/nsAUafYFA1tHPo52TWUm?p=preview" rel="noreferrer">http://plnkr.co/edit/nsAUafYFA1tHPo52TWUm?p=preview</a></li>
  <li>jsfiddle: <a href="http://jsfiddle.net/rnL84/" rel="noreferrer">http://jsfiddle.net/rnL84/</a></li>
  </ul>
  <p>Why the jsfiddle one works well but the plunker one doesn't work? They have exactly the same code, and there is no error in the console.</p>