code: function(event) {
          var changed = false;
          if(this.features) {
              if(this.num === null) {
                  this.num = -1;
              }
              var start = (this.num + 1) * this.length;
              changed = this.page(start, event);
          }
          return changed;
      }
docs: APIMethod: pageNext
  Display the next page of features.
  
  Returns:
  {Boolean} A new page was displayed.