code: function() {
          var NAV = YAHOO.widget.CalendarNavigator;
  
          var yr = null;
          if (this.yearEl) {
              var value = this.yearEl.value;
              value = value.replace(NAV.TRIM, "$1");
  
              if (NAV.YR_PATTERN.test(value)) {
                  yr = parseInt(value, 10);
              }
          }
          return yr;
      }
docs: Returns the year value, from the Navitator's year UI element
  @protected
  @method _getYearFromUI
  @return {Number} The year value set in the UI, if valid. null is returned if
  the UI does not contain a valid year value.