public string GetReCaptchaResponse(bool noScriptUrl)
        {
            if (string.IsNullOrEmpty(siteSource)) return null;

            // Sprawdź czy trzeba rozwiązać ReCaptche
            bool isReCaptchaAvailable = (siteSource.Contains("recaptcha_response_field") && siteSource.Contains("recaptcha_challenge_field"));
            string recaptchaResponseField;

            if (isReCaptchaAvailable)
            {
                // Wyłuskaj klucz publiczny
                string publicKey = Regex.Match(siteSource, "challenge\\?k=(?<publicKey>[^\"']+)").Groups["publicKey"].Value.Trim();
                if (string.IsNullOrEmpty(publicKey)) return null;

                string recaptchaSrc = string.Empty;
                if (noScriptUrl)
                    recaptchaSrc = webHelper.DownloadStuff(ChallengeNoScriptUrl + publicKey);
                else
                    recaptchaSrc = webHelper.DownloadStuff(ChallengeUrl + publicKey);

                // Wyłuskaj kod 'challenge', który posłuży do wczytania obrazka
                string recaptchaChallengeField = string.Empty;
                if (!noScriptUrl)
                {
                    recaptchaChallengeField =
                        Challenge =
                        Regex.Match(recaptchaSrc, "challenge : '(?<challenge>[^']+)'\\,").Groups["challenge"].Value.Trim
                            ();
                    if (string.IsNullOrEmpty(recaptchaChallengeField)) return null;
                }

                string recaptchaImageUrl = string.Empty;
                if (noScriptUrl)
                {
                    this.Challenge =
                        Regex.Match(recaptchaSrc, "image\\?c\\=(?<challenge>[^\"]+)").Groups["challenge"].Value;
                    recaptchaImageUrl = ImageUrl
                                        + this.Challenge;
                }
                else
                    recaptchaImageUrl = ImageUrl + recaptchaChallengeField;

                // Pobierz obrazek
                Image recaptchaImage = Image.FromStream(new MemoryStream(webHelper.DownloadData(recaptchaImageUrl)));
                if (recaptchaImage.Width == 0) return null;

                FormLoginCaptcha captchaForm = new FormLoginCaptcha(recaptchaImage, siteBriefDescription);
                captchaForm.ShowDialog();
                recaptchaResponseField = captchaForm.GetCaptchaText();
            }
            else return null;

            return recaptchaResponseField;
        }