<!DOCTYPE html>
<html>
<body>

<div id="container">
    <meter id="host" min="0" max="100" value="50"></meter>
</div>

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

var shadowRoot = host.createShadowRoot();
shadowRoot.innerHTML = "<span>no progress</span>"
</script>

</body>
</html>