web api instance property
HTMLOutputElement: validationMessage property
The validationMessage read-only property of the HTMLOutputElement interface returns a string representing a localized message that describes the validation constraints that the <output> control does not satisfy (if any). This is the empty string as <output> elements are not candidates for constraint validation (willValidate is false).
Value
The empty string, "";
Specifications
SpecificationsStandards references are available on the canonical MDN page.
Browser compatibility
Browser compatibilityCompatibility data is available on the canonical MDN page.