SO fiddle

Test Fiddle mainly for SO Questions

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">
<ul>
  <li class="directory"><a href="#">Parent Link</a>
    <ul>
      <li><a href="#">Sibling Link</a></li>
      <li><a href="#">Sibling Link</a></li>
      <li><a href="#">Sibling Link</a></li>
    </ul>
  </li>
  <li class="directory"><a href="#">Parent 2 Link</a>
    <ul>
      <li><a href="#">Sibling Link</a></li>
      <li><a href="#">Sibling Link</a></li>
      <li><a href="#">Sibling Link</a></li>
    </ul>
  </li>
</ul>

CSS

.expanded > a { font-weight: bold; }

JavaScript

$(function() {
  $('li.directory').click(function () {
    $(this).toggleClass('expanded').children('ul').slideToggle('slow');
  }).children('ul').hide().click(function(e) {
    e.stopPropagation();
  });
});