Question

I’m trying to prove that changing document.domain can be used only for cross scripting on the same upper level domain. For example if i will try to change document.domain to “google.com” on page which is located on http://www.test.com I will get a security exception in FF. Does anybody know where to locate an official proof of that?

Answer 1

Check out : developer.mozilla.org/same-origin-policy

Here is an excerpt from the site:

There is one exception to the same
origin rule. A script can set the
value of document.domain to a suffix
of the current domain. If it does so,
the shorter domain is used for
subsequent origin checks. For example,
assume a script in the document at
http://store.company.com/dir/other.html
executes the following statement:

document.domain = "company.com";

After
that statement executes, the page
would pass the origin check with
http://company.com/dir/page.html.
However, by the same reasoning,
company.com could not set
document.domain to othercompany.com.