function QueryString(fieldName) { var urlString = document.location.search; if (urlString != null) { var typeQu = fieldName + "="; var urlEnd = urlString.indexOf(typeQu); if (urlEnd != -1) { var paramsUrl = urlString.substring(urlEnd + typeQu.length); var isEnd = paramsUrl.indexOf('&'); if (isEnd != -1) { return paramsUrl.substring(0, isEnd); } else { return paramsUrl; } } else { return null; } } else { return null; } }