For non-leap years, this function returns the same for month 6 (Adar I) and month 7 (Adar II), so, for example:
JewishToJD(6,15,5766) === JewishToJD(7,15,5766)
JDToJewish(JewishToJD(7,15,5766)) === '6/15/5766'
(PHP 4, PHP 5)
JewishToJD — Converts a date in the Jewish Calendar to Julian Day Count
Although this function can handle dates all the way back to the year 1 (3761 B.C.), such use may not be meaningful. The Jewish calendar has been in use for several thousand years, but in the early days there was no formula to determine the start of a month. A new month was started when the new moon was first observed.
The month as a number from 1 to 13
The day as a number from 1 to 30
The year as a number between 1 and 9999
The julian day for the given jewish date as an integer.
JewishToJD returns 0 when the day number is 31 or more.
However, when the day number is 30, JewishToJD returns a valid Julian Day, even when the month only has 29 days. So, for example:
JDToJewish(JewishToJD(4,30,5767)) === "5/1/5767"