checkdate
Description
bool checkdate ( int month, int day, int year)Returns TRUE if the date given is valid; otherwise returns FALSE. Checks the validity of the date formed by the arguments. A date is considered valid if:
year is between 1 and 32767 inclusive
month is between 1 and 12 inclusive
Day is within the allowed number of days for the given month. Leap years are taken into consideration.
See also mktime() and strtotime().