Accordion 2.0 by Kevin Miller

Kevin Miller has updated  to version 2.0 his extraordinary  AJAX  control ACCORDION

New futures:

• Open/Close functionality added (Click on an active accordion).
• Nested Vertical Accordions
• Accordions will dynamically resize on content added REAL TIME!
• ...lots of bug fixes!

 Very simple using:

Include 3 JavaScript files to HTML page

<script type="text/javascript" 
src="javascript/prototype.js"></script>
<script type="text/javascript"
src="javascript/effects.js"></script>
<script type="text/javascript"
src="javascript/accordion.js"></script>

and...

<h2 class="accordion_toggle">Title Bar</h2>
<div class="accordion_content">...</div>
...
...
...
<h2 class="accordion_toggle">Title Bar</h2>
<div class="accordion_content">...</div>

More option see here (In toggle "How to use")