selectlist-listbox-element-ref.html

<!DOCTYPE html>
<script src="support/fake-selectlist.js"></script>
<body>
<script>
const selectlist = createFakeSelectlist('button', /*includeListbox=*/true);
document.body.appendChild(selectlist);

selectlist.querySelector('button').remove();
selectlist.insertAdjacentHTML('afterbegin', `<button>button</button>`);

const listbox = selectlist.querySelector('.fake-selectlist-listbox');
listbox.innerHTML = `
  <option id=optone tabindex=0>one</option>
  <option>two</option>
`;
document.getElementById('optone').focus();
</script>

chromium/third_party/blink/web_tests/external/wpt/html/semantics/forms/the-selectlist-element/selectlist-listbox-element-ref.html