echo "<input type='checkbox' name='subscribe' value='yes'/> 验证数据";
if (isset($_POST['subscribe'])) {
if ($_POST['subscribe'] == $value) {
$subscribed = true;
} else {
$subscribed = false;
print '提交的复选框值无效。';
}
} else {
$subscribed = false;
}
if ($subscribed) {
print '验证有效！';
} else {
print '验证无效！';
}