Cookies Across Multiple Domains

[jeditdog]

When I log into Gmail, Blogger.com also is aware of my logged in session.
Same with Yahoo-Mail & Flicker.

How do they do this?:confused: I assume with Cookies, but isn't it pretty difficult to allow one domain to access another domain's cookie?

thanks
(sorry if this is the wrong forum-subject, I really wasn't sure but figured it applied equally to all server-side languages)

[NogDog]

I would guess that they are using image files or other objects loaded from the respective remote sites, and the files that are accessed for those images/objects are actually scripts that can process the cookies for their domains. But like I said, that's just a (educated) guess.

[chazzy]

actually blogger is part of the google network; which uses an integrated SSO system for handling logins. even without needing a cookie i'm sure they have a query api for looking up who's logged in.

in actuality though, both google.com and blogger.com domains have a SID cookie. they have the same value for me.

how they do it though, it's part of the login process i'm sure. the beauty of ajax is that you can visit a site without actually having to visit a site.