selectlist-selected-value-slot-ref.html

<!DOCTYPE html>
<script src="support/fake-selectlist.js"></script>
<body>
<script>
  const selectlist = createFakeSelectlist('hello world');
  document.body.appendChild(selectlist);

  const oldSelectedValue = selectlist.querySelector('.fake-selectlist-selected-value');
  const newSelectedValue = document.createElement('div');
  newSelectedValue.textContent = 'new selected value';

  replaceChildElement(newSelectedValue, oldSelectedValue);
</script>

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