@financial-times/o-forms/demos/src/demo.js

This component provides responsive styling for form fields and inputs. It provides validation and error handling for forms, as well.

import '../../main.js';

document.addEventListener("DOMContentLoaded", function () {
	document.dispatchEvent(new CustomEvent('o.DOMContentLoaded'));
});

const extraContentInput = document.querySelector("input[name='extra']");
// indeterminate states can only be set dynamically, there is no attribute for them.
if (extraContentInput) { extraContentInput.indeterminate = true; }