title: Javascript cross domain - "allow" other domains?
body: <p><strong>Description of steps</strong></p>
  
  <ol>
  <li>Write "callback" function on my custom page in my domain (called "MyCallbackCallback", for the sake of argument)</li>
  <li>Open new window (from different domain) and pass function name in as part of query string</li>
  <li>New window does what it needs to do then tries to access "MyCallback" from my custom page</li>
  </ol>
  
  <p>This obviously <strong>won't</strong> work and will return "Access denied" error.</p>
  
  <p>If there was a way of "allowing" the 3rd-party domain access to my domain that would solve the issue, of course. Is there such a thing? I know there is in Action Script, but JavaScript?? </p>
  
  <p>NB - I am aware that setting "document.domain" on both pages, (or creating both pages in the same domain) will solve the issue, but I almost certainly <strong>won't</strong> have this option.</p>
  
  <p>If the answer is "you can't" that's fine - I just need to know. I have spent many hours searching and can't find a simple answer (there may not be one!)</p>
  
  <p>Ta, Rob</p>