<!DOCTYPE html>

<html>
<head>
    <style>
        .fixed {
            position: fixed;
            top: 50px;
            left: 50px;
        }
        
        .box {
            height: 100px;
            width: 100px;
            background-color: blue;
        }
        
        .child {
            position: relative;
            left: 50px;
            top: 50px;
        }
        #output {
            margin-top: 520px;
        }
    </style>
    <script src="resources/wheel-handler-region-helper.js"></script>
    <script>
        function dumpRegion()
        {
            if (window.internals) {
                var rects = window.internals.nonFastScrollableRects();
                document.getElementById('output').textContent = rectsAsString(rects);
            }
        }

        window.addEventListener('load', dumpRegion, false);
    </script>
</head>
<body>

<div class="box">
    <div class="fixed box" onmousewheel="(void)0">
    </div>
</div>

<pre id="output"></pre>

</body>
</html>