chromium/content/test/data/accessibility/aria/aria-modal-move-focus.html

<!DOCTYPE html>
<html>
<body onload="loaded()">
  <div role="dialog">Nonmodal</div>
  <button id="outerButton">Outer Button</button>
  <div role="dialog" aria-label="modal dialog" aria-modal="true">
    <button id="innerButton">Inner Button</button>
  </div>
  <script>
    // Test that when focus moves out of an active ARIA modal dialog, the dialog
    // is no onger considered "active", and contet outside the dialog is no
    // longer pruned from the accessibility tree.

    // Note: This test checks an edge case in the aria-modal pruning logic. This
    // logic currently only runs on Mac, so there are only mac expectations for
    // this test. See aria-modal.html for more information on tree pruning.
    function loaded() {
      innerButton.focus();
      outerButton.focus();
    }
  </script>
</body>
</html>