How to get the domain value for a cookie in Javascript?

Question

Using JavaScript I'd like to get the domain value for a specific cookie.

Is this possible? If so, how?

To clarify: I'm not looking for the value of the cookie. I'm on subdomain.example.com and I need to remove a cookie whose name is known but its domain value is something like .example.com. In short: I'd like to get the value of .example.com.

Answer 1

Sorry, all you get is what you see in document.cookie. The cookie metadata like path, domain and expires are not visible to site code (neither to JavaScript nor to the server-side).

To read a cookie that is being shadowed by a cookie with a more-specific domain or path, the only thing you can do is load a page for which the more-specific cookie is out-of-scope, and read it from there.

If, as you say, you only need to remove a cookie, what you could do is try to remove the cookie at every possible level of specificity, eg.:

    document.cookie= 'foo=;domain=sub.domain.example.com;expires=Sat, 01-Jan-2000 00:00:00 GMT';
    document.cookie= 'foo=;domain=domain.example.com;expires=Sat, 01-Jan-2000 00:00:00 GMT';
    document.cookie= 'foo=;domain=example.com;expires=Sat, 01-Jan-2000 00:00:00 GMT';

and similarly with the path variable. You could put this in a nested loop for each path and domain part, splitting on . for the domain and / for the path.

Answer 2

You can only access cookies from the same domain (this includes subdomains). Obviously doing otherwise would be a security concern.