(PHP 4, PHP 5, PHP 7)
Converts a Gregorian date to Julian Day Count
int gregoriantojd ( int $month, int $day, int $year )
Valid Range for Gregorian Calendar 4714 B.C. to 9999 A.D.
Although this function can handle dates all the way back to 4714 B.C., such use may not be meaningful. The Gregorian calendar was not instituted until October 15, 1582 (or October 5, 1582 in the Julian calendar). Some countries did not accept it u