code: function(date, preventOnSelect)
          {
              if (!date) {
                  this._d = null;
                  return this.draw();
              }
              if (typeof date === 'string') {
                  date = new Date(Date.parse(date));
              }
              if (!isDate(date)) {
                  return;
              }
  
              var min = this._o.minDate,
                  max = this._o.maxDate;
  
              if (isDate(min) && date < min) {
                  date = min;
              } else if (isDate(max) && date > max) {
                  date = max;
              }
  
              this._d = new Date(date.getTime());
              setToStartOfDay(this._d);
              this.gotoDate(this._d);
  
              if (this._o.field) {
                  this._o.field.value = this.toString();
                  fireEvent(this._o.field, 'change', { firedBy: this });
              }
              if (!preventOnSelect && typeof this._o.onSelect === 'function') {
                  this._o.onSelect.call(this, this.getDate());
              }
          }
docs: set the current selection