(PHP 4 >= 4.1.0, PHP 5)
cal_days_in_month — Return the number of days in a month for a given year and calendar
This function will return the number of days in the month of year for the specified calendar .
Calendar to use for calculation
Month in the selected calendar
Year in the selected calendar
The length in days of the selected month in the given calendar
Example #1 cal_days_in_month() example
<?php
$num = cal_days_in_month(CAL_GREGORIAN, 8, 2003); // 31
echo "There was $num days in August 2003";
?>