files/en-us/web/api/htmloutputelement/validity/index.md
{{APIRef("HTML DOM")}}
The validity read-only property of the {{domxref("HTMLOutputElement")}} interface returns a {{domxref("ValidityState")}} object that represents the validity states this element is in. Although {{HTMLElement("output")}} elements are never candidates for constraint validation, the validity state may still be invalid if a custom validity message has been set.
A {{domxref("ValidityState")}} object.
The following example demonstrates that an <output> is in an invalid state when a {{domxref("ValidityState/customError", "customError")}} is set; in this state, {{domxref("HTMLOutputElement/checkValidity", "checkValidity()")}} returns true while the validityState's validity property is false.
const output = document.getElementById("myOutput");
output.setCustomValidity("This object element is invalid.");
const validityState = output.validity;
console.log(validityState.valid); // false
console.log(validityState.customError); // true
console.log(output.checkValidity()); // true
{{Specifications}}
{{Compat}}