Can $_COOKIE ever contain cookies set by another domain?

Question

Suppose I have a website www.mysite.com.

Can the $_COOKIE array ever contain cookies that were set by domains other than www.mysite.com, if I am using $_COOKIE via PHP code on the domain www.mysite.com?

My understanding (which is quite limited!) is that a domain can only access cookies that it set itself, which means that $_COOKIE could only contain cookies which were set by the domain. Is this correct?

Answer 1

No. Only a nonfunctional browser would do such a thing.

Only the client can view all the cookies for all separate domains, the browser makes sure to send only the cookies related to the current domain and non other.