public async Task <string> GetActiveElement(CancellationToken cancellationToken = default(CancellationToken))
        {
            await asyncFirefoxDriver.CheckConnected(cancellationToken).ConfigureAwait(false);

            if (asyncFirefoxDriver.ClientMarionette == null)
            {
                throw new Exception("error: no clientMarionette");
            }
            var comm1 = new GetActiveElementCommand();
            await asyncFirefoxDriver.ClientMarionette.SendRequestAsync(comm1, cancellationToken).ConfigureAwait(false);

            if (comm1.Error != null)
            {
                throw new WebBrowserException(comm1.Error);
            }
            return(FirefoxDriverElements.GetElementFromResponse(comm1.Result));
        }
 internal static string ElementId(JToken result)
 {
     return(FirefoxDriverElements.GetElementFromResponse(result));
 }