GlobalEventHandlers.oninvalid

The oninvalid property of the GlobalEventHandlers mixin is an EventHandler that processes invalid events.

The invalid event fires when a submittable element has been checked and doesn't satisfy its constraints. The validity of submittable elements is checked before submitting their owner form, or after the checkValidity() method of the element or its owner form is called.

Syntax

target.oninvalid = functionRef;
var functionRef = target.oninvalid;

Value

functionRef is a function name or a function expression. The function receives a Event object as its sole argument.

Example

This example demonstrates oninvalid and onsubmit event handlers on a form.

HTML

<form id="form">
  <p id="error" hidden>Please fill out all fields.</p>

  <label for="city">City</label>
  <input type="text" id="city" required>

  <button type="submit">Submit</button>
</form>
<p id="thanks" hidden>Your data has been received. Thanks!</p>

JavaScript

const form = document.getElementById('form');
const error = document.getElementById('error');
const city = document.getElementById('city');
const thanks = document.getElementById('thanks');

city.oninvalid = invalid;
form.onsubmit = submit;

function invalid(event) {
  error.removeAttribute('hidden');
}

function submit(event) {
  form.setAttribute('hidden', '');
  thanks.removeAttribute('hidden');

  // For this example, don't actually submit the form
  event.preventDefault();
}

Result

Specification

Browser compatibility

See also

• invalid event
• DOM on-event handlers