<!DOCTYPE html> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script src="resources/open-blank-host.js"></script> <script> promise_test(async () => { assert_implements("HTMLPortalElement" in self); var win = await openBlankPortalHost(); var portal = win.document.createElement("portal"); portal.src = new URL("resources/simple-portal.html", location.href) await new Promise((resolve, reject) => { portal.onload = resolve; win.document.body.appendChild(portal); }); return portal.activate(); }); </script>