<!DOCTYPE html>

<html>
<head>
    <style>
        body {
            background-image: repeating-linear-gradient(white, silver 300px);
        }
    </style>
    
    <script>
        function doTest()
        {
            window.setTimeout(function() {
                document.body.style.height = "2000px";
                window.parent.frameDidChange();
            }, 0);
        }
        window.addEventListener('load', doTest, false);
    </script>
</head>
<body>
</body>
</html>