<!DOCTYPE html>

<html>
<head>
    <style>
        .fixed {
            position: fixed;
            border: 1px solid red;
        }
        
        .removed {
            display: none;
        }
        
    </style>
    <script>
        function subframeLoaded()
        {
            window.setTimeout(function() {
                document.getElementById('container').classList.add('removed');
                window.parent.childFrameTestDone();
            }, 0);
        }
    </script>
</head>
<body>
    <div class="fixed" id="container">
        <iframe onload="subframeLoaded()" src="leaf-frame.html"></iframe>
    </div>
</body>
</html>