JS Warnings for dropdowns

Created by: raad

So going to:

http://twitter.github.com/bootstrap/components.html#navs

with Firefox 14.0.1, on Windows7, and clicking any dropdown, shows the following warning in the Firebug console:

Empty string passed to getElementById(). http://twitter.github.com/bootstrap/assets/js/jquery.js Line 150

Not uber-critical, but nevertheless annoying when you're trying to debug.