Firefox supports the concept of signed scripts (http://www.mozilla.org/projects/security/components/signed-scripts.html) Signed scripts in FF can bypass the same origin check when reading and writing data from cross-domain urls (e.g. cross-domain url in an iframe or opened in a pop-up window). Is there something similar that IE supports? Also, I added 2 domains, domain.com, and domain2.com to the Trusted sites. I removed all access restrictions from the Trusted sites zone. I wanted to access domain2.com DOM opened in a pop-up/iframe from domain1.com, but even after adding both of them to Trusted zone, and removing any restrictions, I am unable to do so. Am I doing something wrong, or this is not possible at all??