anchor.diff:      }
       if (!ignoreClick) {
         _window.onClick.listen((e) {
  -        if (e.target is html.AnchorElement) {
  -          html.AnchorElement anchor = e.target;
  +        if (e.target is AnchorElement) {
  +          AnchorElement anchor = e.target;
             if (anchor.host == _window.location.host) {
               var fragment = (anchor.hash == '') ? '' : '${anchor.hash}';
               gotoUrl("${anchor.pathname}$fragment", anchor.title);
  
positive.code:  */
  class Router {
    final Map<String, _Route> _routes = new Map<String, _Route>();
    bool _useFragment;
    _Route _defaultRoute;
    _Route _currentRoute;
    String _lastTail = '';
    html.Window _window;
  
    /**
     * [useFragment] determines whether this Router uses pure paths with
  
negative.code: 
    void _go(String path, String title) {
      title = (title == null) ? '' : title;
      if (useFragment) {
        _window.location.assign('#$path');
        (_window.document as HtmlDocument).title = title;
      } else {
        _window.history.pushState(null, title, path);
      }
  