PHP Durasi Hari

function rentangHari($startDate, $endDate=null){
    $now = $endDate ? strtotime($endDate) : time();
    $begin = strtotime($startDate);
    $datediff = $now - $begin;
    $output = floor($datediff/(60*60*24));
    return $output;
}

// contoh 1
$rentang = rentangHari('2014-05-17');
echo $rentang; // output: 2

// contoh 2
$tgl1 = '2014-05-17';
$tgl2 = '2014-05-22';
$rentang = rentangHari($tgl1,$tgl2);
echo $rentang; // output: 5