examples/contextual.html

<!DOCTYPE html>
<title> Contextual Fragment </title>

<div id="host"></div>

<script type="module">
  let host = document.querySelector('#host');
  let shadow = host.attachShadow({ mode:'closed' });
  let content = `<script>alert('SCRIPT DID EXECUTE');`;
  let fragment = document.createRange().createContextualFragment(content);
  shadow.append(document.importNode(fragment, true));
</script>