it is not valid HTML to enclose an li tag in an anchor tag:
<a href="javascript:toggleLayer('advSpecs');" title="Advanced Specifications">
<li>Click for Advanced Specifications</li>
</a>
instead, the anchor tag needs to be nested inside the LI tag:
<li><a href="javascript:toggleLayer('advSpecs');" title="Advanced Specifications">Click for Advanced Specifications</a></li>