How to make parent/child checkboxes.

checkboxes.js

document.querySelector('form').addEventListener('input', (event) => {
    let match;
    if (match = /child-(\d+)/.exec(event.target.id) && event.target.checked) {
        document.querySelector(`#parent-${match[1]}`).checked = true;
    }

    if (match = /parent-(\d+)/.exec(event.target.id) && !event.target.checked) {
        document.querySelector(`#child-${match[1]}`).checked = false;
    }
});