chromium/content/test/data/accessibility/event/aria-current-changed.html

<nav>
  <ul>
    <li id="home"><a href="/" aria-current="page">Home</a></li>
    <li id="about"><a href="/">About</a></li>
  </ul>
</nav>
<script>
  function go() {
    // Move aria-curent=page from "Home" to "About".
    document.getElementById('home').removeAttribute('aria-current');
    document.getElementById('about').setAttribute('aria-current', 'page');
  }
</script>