code: function _getHash() {
          var i, href;
          href = top.location.href;
          i = href.indexOf("#");
          return i >= 0 ? href.substr(i + 1) : null;
      }
docs: location.hash is a bit buggy on Opera. I have seen instances where
  navigating the history using the back/forward buttons, and hence
  changing the URL, would not change location.hash. That's ok, the
  implementation of an equivalent is trivial.
  
  @method _getHash
  @return {string} The hash portion of the document's location
  @private