<!DOCTYPE html>
<html>
<body>
<script src="resources/polyfill.js"></script>

<form>
    <textarea id="host" cols="20" rows="4">Something in the air</textarea>
</form>

<script>
if (window.internals)
    internals.settings.setAuthorShadowDOMForAnyElementEnabled(true);

var shadowRoot = host.webkitCreateShadowRoot();

var div = document.createElement('div');
div.innerHTML = "(before)<shadow></shadow>(after)";
shadowRoot.appendChild(div);
</script>

</body>
</html>