title: "HTMLOutputElement: validationMessage property"

short-title: validationMessage

slug: Web/API/HTMLOutputElement/validationMessage

page-type: web-api-instance-property

browser-compat: api.HTMLOutputElement.validationMessage

{{APIRef("HTML DOM")}}

The **`validationMessage`** read-only property of the {{domxref("HTMLOutputElement")}} interface returns a string representing a localized message that describes the validation constraints that the {{htmlelement("output")}} control does not satisfy (if any). This is the empty string as `<output>` elements are not candidates for constraint validation ({{domxref("HTMLOutputElement.willValidate")}} is `false`).