code: function(elem, offset) {
  			var inst = this._getInst(elem);
  			if (!$.isEmptyObject(inst)) {
  				var date = inst.drawDate.newDate().add(offset, 'm');
  				this.showMonth(elem, date.year(), date.month());
  			}
  		}
docs: Adjust the currently shown month.
  @memberof CalendarsPicker
  @param elem {Element} The control to affect.
  @param offset {number} The number of months to change by.
  @example $(selector).datepick('changeMonth', 2)