What is this style of navigation sidebar called and is there an open source Javascript library for it?
<p>I'd like to build a sidebar navigation for an online book much like apple did here:</p>

<p><a href="http://developer.apple.com/library/ios/navigation/" rel="nofollow">http://developer.apple.com/library/ios/navigation/</a></p>

<p>(note it has collapsable entries)</p>

<p>and to my surprise I'm having a hard time finding a good off the shelve javascript startingpoint to build from.</p>

<p>What is this style of navigation sidebar called?</p>

<p>Are there any open source Javascript libraries that provide this style of navigation?</p>
