Check if several dates are valid Gregorian dates:
The checkdate() function is used to validate a Gregorian date.
|month||Required. Specifies the month as a number between 1 and 12|
|day||Required. Specifies the day as a number between 1 and 31|
|year||Required. Specifies the year as a number between 1 and 32767|
|Return Value:||TRUE if the date is valid. FALSE otherwise|