<html>
<body>
<h1>The DOMToken Object</h1>
<h2>The supports() Method</h2>
<iframe id="myFrame"></iframe>
<p>The ifame supports "allow-nonsense":</p>
<p id="demo"></p>
<script>
const list = document.getElementById("myFrame").sandbox;
document.getElementById("demo").innerHTML = list.supports("allow-nonsense");
</script>
</body>
</html>