code: function(cell) {
      var elCell = this.getTdEl(cell);
      if(elCell) {
          var nThisTdIndex = elCell.cellIndex;
          var elRow = this.getTrEl(elCell);
          if(nThisTdIndex > 0) {
              return elRow.cells[nThisTdIndex-1];
          }
          else {
              var elPreviousRow = this.getPreviousTrEl(elRow);
              if(elPreviousRow) {
                  return this.getLastTdEl(elPreviousRow);
              }
          }
      }
      YAHOO.log("Could not get next TD element for cell " + cell, "info", this.toString());
      return null;
  }
docs: Returns DOM reference to the previous TD element from the given cell, or null.
  
  @method getPreviousTdEl
  @param cell {HTMLElement | String | Object} DOM element reference or string ID, or
  object literal of syntax {record:oRecord, column:oColumn} from which to get previous TD element.
  @return {HTMLElement} Reference to previous TD element, or null.