检查是否设置了第三方cookies

Question

Assuming that the user visits a domain A, how can I check that there is third-party cookies set within an iframe from domain B loaded unter the domain A or not?

Answer 1

You can't check or read any cookie from different domain, your browser will not allow that, except if:

• The Domain A has some JavaScript loaded from Domain B
• The JavaScript set some cookie
• Then the browser allow to send that cookie to Domain B when loaded in Iframe inside Domain A