title: Why would javascript code not be able to access variables in the window that opened it (window.opener) if both windows are from the same domain?
body: <p>I'm trying to use the Facebook Connect Javascript API. I have a Facebook login button on subdomain.example.com/foo/bar/baz/article.html. Clicking on the button opens a login page on Facebook's domain. After you log in, that child window goes to subdomain.example.com/foo/xd_receiver.html, which is a file that Facebook provides that just has a script tag to load a script from their domain which tries to access the original window and call a function from it.</p>
  
  <p>Since the child window and the parent window are both on the same domain, I'd think that the child window would be able to access properties of the parent's window object (and not just location). It can't for some reason. Thoughts?</p>
  
  <p>The documentation says that the xd_receiver file needs to be in a location where a relative path (without '..', I presume) can access it from whatever page the login button is on, but says that an absolute path will work in Firefox, which is what I'm using. The xd_receiver file is loading, so I don't think that's the problem. Anyone know why such a restriction would exist anyway? The documentation is fond of saying 'do this' without explaining why. Fun times.</p>