// Register sync method without communicating with Formium object.
        private JavaScriptValue Add(JavaScriptValue[] arguments)
        {
            if (arguments.Length == 2)
            {
                var retval = arguments[0].GetDouble() + arguments[1].GetDouble();

                return(JavaScriptValue.CreateNumber(retval));
            }

            return(JavaScriptValue.CreateNull());
        }