JS2: Task4: Wrap a TreeView into a module.
var controls = …
var treeView = controls.treeView("div.tree-view");
var jsnode=treeView.addNode();
jsnode.content("JavaScript");
var js1subnode = jsnode.addNode();
js1subnode.content("JavaScript - part 1");
var js2subnode = jsnode.addNode();
js2subnode.content("JavaScript - part 2");
var jslibssubnode = jsnode.addNode();
jslibssubnode.content("JS Libraries");
var jsframeworksnode = jsnode.addNode();
jsframeworksnode.content("JS Frameworks and UI");

var webnode = treeView.addNode();
webnode.content("Web");

The code above should generate:
<div class="tree-view">
  <ul>
    <li><a href="#">JavaScript</a>
      <ul>
        <li><a href="#">JavaScript - part 1</a></li>
        <li><a href="#">JavaScript - part 2</a></li>
        <li><a href="#">JS Libraries</a></li>
        <li><a href="#">JS Frameworks and UI</a></li>
      </ul>
    </li>
    <li><a href="#">Web</a></li>
  </ul>
</div>