<!DOCTYPE html>
<!-- Used when testing access of a closed/detached window's properties -->
<html>
<body onpagehide="opener.postMessage('closed', '*');">
<script>
opener.postMessage("opened", "*");
</script>
</body>
</html>
<!DOCTYPE html>
<!-- Used when testing access of a closed/detached window's properties -->
<html>
<body onpagehide="opener.postMessage('closed', '*');">
<script>
opener.postMessage("opened", "*");
</script>
</body>
</html>