list.sort(function(a, b) {

          if(typeof a == 'undefined')
          {
              return -1;
          }

          if(typeof b == 'undefined')
          {
              return 1;
          }

          if(typeof a.gridSortOrder == 'undefined')
          {
              return -1;
          }

          if(typeof b.gridSortOrder == 'undefined')
          {
              return 1;
          }

          var aNum = parseInt(a.gridSortOrder);
          var bNum = parseInt(b.gridSortOrder);

        return aNum > bNum;
      });