<?PHP
 
/*
days_in_month($month, $year)
Returns the number of days in a given month and 
year, taking into account leap years.
 
$month: numeric month (integers 1-12)
$year: numeric year (any integer)
 
*/
 
FUNCTION days_in_month($month, $year){
// calculate number of days in a month
RETURN $month == 2 ? ($year % 4 ? 28 : ($year % 100 ? 29 : ($year % 400 ? 28 : 29))) : (($month - 1) % 7 % 2 ? 30 : 31);
}
?>