php根据生日计算年龄

function calculateAge($birthday) {
    $currentDate = date('Y-m-d');
    $birthdayDate = date('Y-m-d', strtotime($birthday));
    $age = date_diff(date_create($currentDate), date_create($birthdayDate))->y;
    return $age;
}

// 使用示例
$birthday = '1990-05-15';
$age = calculateAge($birthday);
echo "年龄是：".$age;