How Get Number of Days in a Month in PHP

Extracted from PHP.net

function days_in_month($month, $year)  { 
return $month == 2 ? 
($year % 4 ? 28 : ($year % 100 ? 29 : ($year % 400 ? 28 : 29))) : 
(($month - 1) % 7 % 2 ? 30 : 31); 
}

echo days_in_month(YOUR_MONTH,YOUR_YEAR);

More Simple way by a SafFunction

function days_in_month($month,$year) {
return date('t',mktime(0,0,0,$month,1,$year));
}

echo days_in_month(YOUR_MONTH,YOUR_YEAR);