How to get cookies from another JS site?

Question

JavaScript

There is 1 site on which, theoretically, every second a request can be sent to the server,
there are 2 sites on which the user's cookies are located,

I need to make sure that before sending a request to the server, 1 site receives the value of a specific cookie from 2 sites, how to implement this ?

Answer 1

No, if these are different domains.
Either one domain, or throwing cookies through a proxy in plain text. Obviously, in this case, you need access to both sites.