code: function validateCaptcha(captchaKey, captchaValue, callback) {
  
    // callback = function(err, isValid) {...}
    sweetcaptcha.api('check', {sckey: captchaKey, scvalue: captchaValue}, function(err, response){
      if (err) return callback(err);
  
      if (response === 'true') {
        // valid captcha
        return callback(null, true); 
      }
  
      // invalid captcha
      callback(null, false);
  
    });
    
  }
docs: Validate using sckey and scvalue, hidden inputs from previous HTML