<!DOCTYPE html> <title>Return fullscreen permissions policy state from self and a sandboxed child frame</title> <script> "use strict"; window.onload = () => { let frame = document.createElement('iframe'); frame.src = "/permissions-policy/resources/nested-sandbox.html"; frame.sandbox = "allow-scripts"; var handle_message = evt => { if (evt.source === frame.contentWindow) { window.parent.postMessage({ "child": document.featurePolicy.allowedFeatures().includes("fullscreen"), "grandchild": evt.data },"*"); document.body.removeChild(frame); window.removeEventListener('message', handle_message); } }; window.addEventListener('message', handle_message); document.body.appendChild(frame); }; </script>