Getting the current URL of an embedded frame showing a page on an external domain is (or at least should be) impossible due to restrictions on cross-site scripting. This is the same reason why when you view a page that's trapped in a Diggbar-style frame, if you click a link inside the framed site and later close the "bar", you get redirected back to the initial site. Try it: <a href="http://digg.com/u3L7UJ" rel="nofollow">http://digg.com/u3L7UJ</a>