The UIEvent.view read-only property returns the WindowProxy object from which the event was generated. In browsers, this is the Window object the event happened in.
The ValidityState interface represents the validity states that an element can be in, with respect to constraint validation. Together, they help explain why an element's value fails to validate, if it's not valid.
The read-only property ValidityState.badInput indicates if the user has provided input that the browser is unable to convert. For example, if you have a mail input element whose content does not have a '@'.