function getQueryString(urlString,fieldName) { 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; } };