if (isset($_COOKIE['key'])) {
unset($_COOKIE['key']);
setcookie('key', '', time() - 3600, '/'); // empty value and old timestamp
}
unset($_COOKIE['hello']);
// unset cookies
if (isset($_SERVER['HTTP_COOKIE'])) {
$cookies = explode(';', $_SERVER['HTTP_COOKIE']);
foreach($cookies as $cookie) {
$parts = explode('=', $cookie);
$name = trim($parts[0]);
setcookie($name, '', time()-1000);
setcookie($name, '', time()-1000, '/');
}
}