IntegrateIntegration ModesHeadless CheckoutSDK ReferenceInterfacesPaymentElementEventsCallbackOn this pagePaymentElementEventsCallbackProperties fatalError() fatalError: (payload) => void; Handler for fatal error events Parameters ParameterTypepayload{ code: string; internalEventCode: EventCode; reason: string; }payload.codestringpayload.internalEventCodeEventCodepayload.reasonstring Returns void formValid() formValid: (payload) => void; Handler for form validation success events Parameters ParameterTypepayload{ isValid: boolean; }payload.isValidboolean Returns void validationRequested() validationRequested: (payload) => void; Handler for validation request events Parameters ParameterTypepayloadItemPayload Returns void