Php/js cookie sharing across domains

Record a recent cookie The need for sharing ., There are two situations ：

The first one is ： In the case of the same top-level domain name , Only need to cookie Write it under the top-level domain name , All subdomains under this domain name can be accessed . Such as PHP：

//xxx.com    You can't add .  ( Generated cookie Of domain yes  .xxx.com)
setcookie('test','value',time()+60*60*24*30,'/','xxxx.com');

//xxx.com  All subdomains of   Can get 
$_COOKIE['test'];

JS The settings and php similar ：

// Storage cookie, The domain name here must be a top-level domain name 
setCookie('test','value','xxx.com','20')
function setCookie(cName, value,domain,expireDate) {
	const exDate = new Date();
	exDate.setDate(exDate .getDate() + expireDate);
	document.cookie = cName + "=" + decodeURIComponent(value) + (expireDate== null ? "" : ";expires=" + exDate.toUTCString()) + ";path=/;domain="+domain;
}
 
// obtain cookie
getCookie('test')
function getCookie(key) {
    return decodeURIComponent(document.cookie.replace(new RegExp("(?:(?:^|.*;)\\s*" + encodeURIComponent(key).replace(/[-.+*]/g, "\\$&") + "\\s*\\=\\s*([^;]*).*$)|^.*$"), "$1")) || null;
}

The second kind ： Two sites with different top-level domains , It needs to be set in cookie When setting httpOnly、secure、sameSite; such as A Set up cookie,B Can pass jsonp You can get it by the way of .sameSite Must be set to None, The default is an empty . Such as PHP：

php>=7.3 Version can be set directly

setcookie('test','value',[
    'expires'=>time()+60*60*24*30,
    'path'=>'/',
    'domain'=>'xxx.com',
    'httponly'=>true,
    'secure'=>true,
    'samesite'=>'None'
]);

php<7.3

function samesite_setcookie($name, $value, array $options)
{
    $header = 'Set-Cookie:';
    $header .= rawurlencode($name) . '=' . rawurlencode($value) . ';';
    if (isset($options['expires'])) {
        $header .= 'expires=' . \gmdate('D, d-M-Y H:i:s T', $options['expires']) . ';';
    }
    if (isset($options['expires'])) {
        $header .= 'Max-Age=' . max(0, (int) ($options['expires'] - time())) . ';';
    }
    if (!empty($options['path'])) {
        $header .= 'path=' . $options['path']. ';';
    }
    if (!empty($options['domain'])) {
        $header .= 'domain=' . rawurlencode($options['domain']) . ';';
    }
    if (!empty($options['secure'])) {
        $header .= 'Secure;';
    }
    if (!empty($options['httponly'])) {
        $header .= 'HttpOnly;';
    }
    if (!empty($options['samesite'])) {
        $header .= 'SameSite=' . rawurlencode($options['samesite']);
    }
    header($header, false);
    $_COOKIE[$name] = $value;
}

samesite_setcookie('test', 'value', [
    'expires' => time()+60*60*24*30,
    'domain' => 'xxx.com',
    'httponly' => true,
    'samesite' => 'None',
    'secure' => true,
    'path' => '/'
]);