Passing cookie data between iframes

Question

Say I have a website, www.example.com, with a login box which sits in an iframe situated in api.example.com. My question is:

1. Is it possible to pass cookie data from the inner iframe (api.example.com to the website, so the website knows when the user logged in?
2. Is it possible to do this client-side, without the need to refresh the whole page? How would the fact that user logged in be passed to the website?

Any solution which works on FF and IE 6/7 would be great.

Answer 1

You don't have to pass the cookie between them. You need to write the cookie to the right domain though.

Response.Cookies("COOKIENAME").Domain = ".example.com"
Response.Cookies("COOKIENAME").Value= "foo"