Table of content like JavaScript-Garden
<p>I want to create a table of content similar to <a href="http://bonsaiden.github.com/JavaScript-Garden/" rel="nofollow">JavaScript Gardens</a>. How do they determine which section is currently active and do you have any recommended JavaScript libraries that imlpement this behavior?</p>

<p>Edit: So the thing I am asking for is how to know which section currently is active on the screen while the user is scrolling so that I can highlight that section in the table of content.</p>
