t subframeLoaded;

            let iframe = document.querySelector("iframe");
            iframe.contentWindow.postMessage(id, "*");

            await awaitMessage(id);

            const doc = iframe.contentDocument;
            const div = doc.getElementById(id);
            const cdata = div.firstChild;

            return [div, cdata];
        }

        test(function() {
            const div = document.getElementById("test1");
            assert_true(div.matches(":dir(rtl)"));
        }, "Content of 