Are cookies domain-dependent in PHP, and how does this impact the ability to read cookies set by different domains?

Cookies are domain-dependent in PHP, meaning that a cookie set by one domain cannot be read by a different domain due to security restrictions imposed by browsers. To work around this limitation, you can set the domain parameter of the cookie to a common parent domain that both sites share. This will allow the cookie to be read by both domains.

setcookie("cookie_name", "cookie_value", time() + 3600, "/", ".commonparentdomain.com");