chromium/content/test/data/accessibility/event/navigation-api.html

<!--
@AURALINUX-DENY:STATE-CHANGE:DEFUNCT:TRUE*
-->
<!DOCTYPE html>
<!-- https://github.com/wicg/navigation-api -->
<title>Starting title</title>

<main>
  <p>Starting content</p>
</main>

<script>
window.startSecondPass = undefined;

navigation.addEventListener("navigate", ev => {
  ev.intercept({ handler: doTransition });
});

async function doTransition() {
  // Emulate a server round trip which only finishes once the accessibility
  // test harness says the first pass has settled down.
  //
  // In a typical single-page app this would actually be `await fetch(...)` to
  // get the data used below.
  await new Promise(r => { window.startSecondPass = r; });

  // Use the "data we got back from the server" to update the document.
  document.title = "Ending title";
  document.querySelector("main").innerHTML = `<p>Ending content</p>`;
}

let goPass = 1;
window.go = () => {
  if (goPass === 1) {
    location.href = "this-will-be-converted-to-a-same-document-navigation.html";
    ++goPass;
    return true;
  }

  window.startSecondPass();
  return false;
};
</script>