checkdate Validate a Gregorian date &reftitle.description; boolcheckdate intmonth intday intyear Checks the validity of the date formed by the arguments. A date is considered valid if each parameter is properly defined. &reftitle.parameters; month The month is between 1 and 12 inclusive. day The day is within the allowed number of days for the given month. Leap years are taken into consideration. year The year is between 1 and 32767 inclusive. &reftitle.returnvalues; Returns &true; if the date given is valid; otherwise returns &false;. &reftitle.examples; ]]> &example.outputs; &reftitle.seealso; mktime strtotime