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 id="contactOpties">
    <li class="email"><a href="#" class="active">Email</a></li>
    <li class="publicaties"><a href="#">Publicaties</a></li>
    <li class="vcard"><a href="#">Vcard</a></li>
    <li class="meerinfo"><a href="#">Meer info</a></li>
</ul>

CSS

.active { font-weight: bold; color: red; }

JavaScript

$("#contactOpties").delegate("li", "click", function() {
  $(this).children('a').addClass('active').end()
         .siblings().children().removeClass('active');
});