code: protected function load($url, $parameters)
      {
          $frame = $url->getTarget();
          if (! $frame || ! $this->page->hasFrames() || (strtolower($frame) == '_top')) {
              return $this->loadPage($url, $parameters);
          }
  
          return $this->loadFrame(array($frame), $url, $parameters);
      }
docs: Fetches a page or a single frame if that is the current focus.
  
  @param SimpleUrl $url                   Target to fetch.
  @param SimpleEncoding $parameters       GET/POST parameters.
  
  @return string                          Raw content of page.