code: function(year, month, day) {
  			var date = this._validate(year, month, day, $.calendars.local.invalidDate);
  			var year = this._t2gYear(date.year());
  			return gregorianCalendar.toJD(year, date.month(), date.day());
  		}
docs: Retrieve the Julian date equivalent for this date,
  i.e. days since January 1, 4713 BCE Greenwich noon.
  @memberof TaiwanCalendar
  @param year {CDate|number} The date to convert or the year to convert.
  @param [month] {number} The month to convert.
  @param [day] {number} The day to convert.
  @return {number} The equivalent Julian date.
  @throws Error if an invalid date or a different calendar used.