files/en-us/web/api/htmlfieldsetelement/validity/index.md
{{APIRef("HTML DOM")}}
The validity read-only property of the {{domxref("HTMLFieldSetElement")}} interface returns a {{domxref("ValidityState")}} object that represents the validity states this element is in. Although {{HTMLElement("fieldset")}} elements are never candidates for constraint validation, the validity state may still be invalid if a custom validity message has been set.
[!NOTE] The {{cssxref(":valid")}} and {{cssxref(":invalid")}} CSS pseudo-classes are applied to
<fieldset>elements based on the validity of its descendant form controls, not the fieldset itself.
A {{domxref("ValidityState")}} object.
The following example demonstrates that a <fieldset> is in an invalid state when a {{domxref("ValidityState/customError", "customError")}} is set; in this state, {{domxref("HTMLFieldSetElement/checkValidity", "checkValidity()")}} returns true while the validityState's validity property is false.
const fieldSet = document.getElementById("myFieldSet");
fieldSet.setCustomValidity("This fieldset is invalid.");
const validityState = fieldSet.validity;
console.log(validityState.valid); // false
console.log(validityState.customError); // true
console.log(fieldSet.checkValidity()); // true
[!NOTE] The {{cssxref(":valid")}} and {{cssxref(":invalid")}} CSS pseudo-classes are applied to
<fieldset>elements based on the validity of its descendant form controls, not the fieldset itself.
{{Specifications}}
{{Compat}}