Readonly formReturns the form owner of internals's target element.
Readonly labelsReturns a NodeList of all the label elements that internals's target element is associated with.
Readonly shadowReturns the ShadowRoot for internals's target element, if the target element is a shadow host, or null otherwise.
Readonly statesReadonly validationReturns the error message that would be shown to the user if internals's target element was to be checked for validity.
Readonly validityReturns the ValidityState object for internals's target element.
Readonly willReturns true if internals's target element will be validated when the form is submitted; false otherwise.
Marks internals's target element as suffering from the constraints indicated by the flags argument, and sets the element's validation message to message. If anchor is specified, the user agent might use it to indicate problems with the constraints of internals's target element when the form owner is validated interactively or reportValidity() is called.
Optional flags: ValidityStateFlagsOptional message: stringOptional anchor: HTMLElement
MDN Reference