code: function resizeToFit( iframe ) {
     if( !iframe ) {
        // Indicate that the iframe is not there (anymore): Cancel the timeout.
        return false;
     }
  
     const body = iframe.contentDocument && iframe.contentDocument.body;
     if( !body || !body.scrollHeight ) {
        // not ready yet, but keep trying.
        return true;
     }
  
     const html = iframe.contentDocument.documentElement;
     setPixelDimensions( iframe, html.offsetWidth, html.offsetHeight );
     return true;
  }
docs: ////////////////////////////////////////////////////////////////////////////////////////////////////////////