Gentlemen, on the above URL let's examine the links for e.g., "[+] Buses by continent (6 C)"

 <div class="CategoryTreeItem">
  <span class="CategoryTreeBullet"><a href=
  "/wiki/Category:Buses_by_continent" class="CategoryTreeToggle"
onclick="this.href='javascript:void(0)';
   categoryTreeExpandNode('Buses_by_continent',{&quot;mode&quot;:0,&quot;hideprefix&quot;:20,&quot;showcount&quot;:true,&quot;namespaces&quot;:false},this);"
title="expand">[<b>+</b>]</a></span> <a class="CategoryTreeLabel
   CategoryTreeLabelNs14 CategoryTreeLabelCategory" href=
  "/wiki/Category:Buses_by_continent">Buses by continent</a>
  <span title="contains 6 subcategories, 0 pages, and 0 files">(6
  C)</span>
 </div>

The problem is, if the user is using a text browser or any other situation where he is not head over heels about turning on javascript, he just ends up with pairs of the same hyperlink.

Therefore TABing through a page, he has to hit twice as many tabs to get to where he wants, to step over what are now pairs of the same link.

Therefore please make your javascript bonuses only affect users who are using javascript, and not have any negative side effects on those who don't. (Accessibility impact.)

One approach would be to rewrite so the whole first link only appears at all if the user has javascript turned on.

Or maybe a user preference: enable javascript extensions (on by default)...

Anyway, all I know is please test these things in text browsers next time first.

Version: unspecified
Severity: trivial
URL: http://commons.wikimedia.org/wiki/Category:Bus_transport