rem: var thiscat = this.id.split('_')[1]; 
add: var thiscat = catlink.id.split('_')[1]; 
context:                               function()                              {                                   var thiscat = this.id.split('_')[1];                                  $A(document.getElementsByClassName('category')).each(                                      function(cat)                                      {                                          if(cat.id == 'category_' + thiscat) {                                              if(Element.hasClassName(cat, 'hidden')) {                                                  Element.removeClassName(cat, 'hidden');                                              } else {                                                  Element.addClassName(cat, 'hidden');                                              }                                          } else {                                              Element.addClassName(cat, 'hidden');                                          }                                      }                                      );                                  return;                              },
meta: 5124	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5124/2648bc3d3c313f20b467bd35fc82a1afdfa486ac/pnforum_user_main.js/buggy/pnForum/pnjavascript/pnforum_user_main.js