code: function (event) {
          var nick_class;
  
          // Find a valid class that this element has
          _.each($(event.currentTarget).parent('.msg').attr('class').split(' '), function (css_class) {
              if (css_class.match(/^nick_[a-z0-9]+/i)) {
                  nick_class = css_class;
              }
          });
  
          // If no class was found..
          if (!nick_class) return;
  
          $('.'+nick_class).addClass('global_nick_highlight');
      }
docs: Cursor hovers over a message