chromium/content/test/data/accessibility/fullscreen/links.html

<!DOCTYPE html>
<a href="/">link before target</a>
<div id="target">
  <button>Enter fullscreen</button>
  <a href="/">link inside target</a>
</div>
<a href="/">link after target</a>
<script>
const target = document.getElementById('target');

const button = document.querySelector('button');
button.addEventListener('click', function() {
  target.webkitRequestFullscreen();
});

document.onwebkitfullscreenchange = function() {
  button.setAttribute('aria-label', 'Done');
}
</script>