What is it called when a div scrolls as the page scrolls and is there a library written specifically for this?
<p>I'm trying to find out more information about an element that scrolls within a page as the page is scrolled and has an upper and lower bound.  </p>

<p>Specifically, I am trying to add functionality that scrolls my secondary content section (sidebar) within the bounds of my header and footer as the page scrolls.</p>

<p>As an example, Apple uses it in there store when selecting product features to include - <a href="http://store.apple.com/us/configure/MD093LL/A" rel="nofollow">http://store.apple.com/us/configure/MD093LL/A</a>.</p>

<p>I am able to recreate this functionality, but I'm betting I could find code that has been more thoroughly tested, cross-browser compliant, etc. with stackoverflow's help.</p>

<p>Ideally, I would hope to find something that functions on it's own and not as a part of a much larger library like jQuery.  This is just a preference, but I'm open to potential solutions that include a jQuery-type library...</p>
