<!DOCTYPE html>
<title>Element ready check for child of a fullscreen iframe</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script src="../trusted-click.js"></script>
<div id="log"></div>
<iframe><!-- script inserts div here --></iframe>
<script>
    // Verify that an iframe can itself go fullscreen, and that this doesn't
    // influence the iframe ancestor test of the element ready check.
    promise_test(async (t) => {
        document.onfullscreenerror = t.unreached_func("fullscreenerror event");
        const iframe = document.querySelector("iframe");
        await Promise.all([trusted_request(iframe), fullScreenChange()]);

        assert_equals(document.fullscreenElement, iframe, "fullscreen element");

        // This adds the div to the iframe element itself, not to the iframe's
        // contentDocument. It's done here because the HTML parser treats the
        // content of iframe as a text node.
        var div = document.createElement("div");
        iframe.appendChild(div);

        await Promise.all([
            trusted_request(div, iframe.contentDocument.body),
            fullScreenChange(),
        ]);
        assert_equals(document.fullscreenElement, div);
    }, "Element ready check for child of a fullscreen iframe");
</script>
