code: function(year, month, day) {
  			var date = this._validate(year, month, day, $.calendars.local.invalidDate);
  			year = date.year();
  			month = date.month();
  			day = date.day();
  			year = (year <= 0 ? year + 1 : year);
  			return day + Math.ceil(29.5 * (month - 1)) + (year - 1) * 354 +
  				Math.floor((3 + (11 * year)) / 30) + this.jdEpoch - 1;
  		}
docs: Retrieve the Julian date equivalent for this date,
  i.e. days since January 1, 4713 BCE Greenwich noon.
  @memberof IslamicCalendar
  @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.