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<div class="modal" role="dialog" aria-labelledby="Modal_Title" aria-describedby="Modal_Description" aria-hidden="true" style="display: none">
<div class="modal-content">
<h2 id="Modal_Title">Delete Confirmation</h2>
<p id="Modal_Description" class="visually-hidden">Some visually hidden text describing how to use the modal.</p>
<input type="text" value="first focusable element"><br><br>
<button class="close-modal">Close Modal</button>
</div>
</div>
<main>
<button class="open-modal">Open Modal</button>
<br>
<br>
<br>
<button>This element shouldnt receive focus when the modal is open</button>
</main>
.modal {
position: fixed;
background: rgba(0, 0, 0, .6);
top: 0;
left: 0;
right: 0;
bottom: 0;
padding: 20px;
display: flex;
align-items: center;
justify-content: center;
flex-direction: column;
}
.modal-content {
width: 250px;
height: 250px;
background: white;
padding: 20px;
}
.visually-hidden {
position: absolute !important;
height: 1px; width: 1px;
overflow: hidden;
clip: rect(1px, 1px, 1px, 1px);
}
*:focus {
outline: 3px dashed blue;
}
// Open this pen in debug mode for testing
// https://codepen.io/noahblon/debug/yJpXZa
// This is a sketch of some principles of an accessible modal - trying to keep it simple. For a more complete demonstration, check out: https://github.com/gdkraus/accessible-modal-dialog
const FOCUSABLE_SELECTORS = 'a[href], area[href], input:not([disabled]), select:not([disabled]), textarea:not([disabled]), button:not([disabled]), iframe, object, embed, *[tabindex], *[contenteditable]';
const openModalBtn = document.querySelector('.open-modal');
const closeModalBtn = document.querySelector('.close-modal');
const modal = document.querySelector('.modal');
const main = document.querySelector('main');
function openModal() {
// show the modal
modal.style.display = 'flex';
// Focus the first element within the modal. Make sure the element is visible and doesnt have focus disabled (tabindex=-1);
modal.querySelector(FOCUSABLE_SELECTORS).focus();
// Trap the tab focus by disable tabbing on all elements outside of your modal. Because the modal is a sibling of main, this is easier. Make sure to check if the element is visible, or already has a tabindex so you can restore it when you untrap.
const focusableElements = main.querySelectorAll(FOCUSABLE_SELECTORS);
focusableElements.forEach(el => el.setAttribute('tabindex', '-1'));
// Trap the screen reader focus as well with aria roles. This is much easier as our main and modal elements are siblings, otherwise you'd have to set aria-hidden on every screen reader focusable element not in the modal.
modal.removeAttribute('aria-hidden');
main.setAttribute('aria-hidden', 'true');
}
function closeModal() {
// hide the modal
modal.style.display = 'none';
// Untrap the tab focus by removing tabindex=-1. You should restore previous values if an element had them.
const focusableElements = main.querySelectorAll(FOCUSABLE_SELECTORS);
focusableElements.forEach(el => el.removeAttribute('tabindex'));
// Untrap screen reader focus
modal.setAttribute('aria-hidden', 'true');
main.removeAttribute('aria-hidden');
// restore focus to the triggering element
openModalBtn.focus();
}
openModalBtn.addEventListener('click', openModal);
closeModalBtn.addEventListener('click', closeModal);
Also see: Tab Triggers