recaptcha how to get response opt_widget_id code example

Example: Request["g-recaptcha-response"]

string EncodedResponse = Request.Form["g-Recaptcha-Response"];
bool IsCaptchaValid = (ReCaptchaClass.Validate(EncodedResponse) == "true" ? true : false);

if (IsCaptchaValid) {
    //Valid Request
}