| <!-- | |
| Copyright 2022 The Chromium Authors | |
| Use of this source code is governed by a BSD-style license that can be | |
| found in the LICENSE file. | |
| --> | |
| <!doctype html> | |
| <div id="host"> | |
| <h1>headline</h1> | |
| </div> | |
| <script> | |
| const host = document.querySelector('#host'); | |
| const shadow = host.attachShadow({mode: 'open'}); | |
| const slot = document.createElement('slot'); | |
| shadow.appendChild(slot); | |
| </script> |