anchor.diff:        return url;
       }
     }
  +
  +  //----------------------------------------------------------------
  +  /// Returns hidden form parameter input to include the session parameter.
  +  ///
  +  /// If there is no session (i.e. session is null) or cookies are being used
  +  /// to preserve the session, returns the empty string.
  +
  +  String sessionFormHiddenParameter() {
  +    if (hasSession && !this._sessionUsingCookies) {
  +      // Require hidden POST form parameter to preserve session
  +      return "<input type=\"hidden\" name=\"" +
  +        HEsc.attr(_server.sessionParamName) +
  +          "\" value=\"" +
  +        HEsc.attr(session.id) +
  +        "\"/>";
  +    } else {
  +      return ""; // hidden POST form parameter not required
  +    }
  +  }
   }
  
positive.code: 
    String get method => _request.method;
  
    //================================================================
    // Session
  
  
negative.code:   /// needs to explicitly delete a cookie if the session is cleared.
  
    bool _sessionWasSetInRequest;
  
    /// Indicates if the request has a session or not.
  
    bool get hasSession => session != null;
  
    //================================================================
    /// The three different sources of parameters.
  