checkValidity

The checkValidity() method of the HTMLButtonElement interface returns a boolean value which indicates if the element meets any constraint validation rules applied to it. If false, the method also fires an invalid event on the element. Because there's no default browser behavior for checkValidity(), canceling this invalid event has no effect. It always returns true if the element's type is "button" or "reset", because such buttons are never candidates for constraint validation.

MDN Reference