<frameset cols="*">
    <frame src="data:text/html,
        <script>
            function contextMenu()
            {
                document.getElementById('result').appendChild(document.createTextNode('PASS'));
            }
        </script>
        <body onmousedown='return false;' oncontextmenu='contextMenu(); return false;'>
            <p>
                Control-click (Mac) or right-click (Windows) below. The word 
                %26ldquo;PASS%26rdquo; should appear. A contextual menu should not open.
            </p>
            <p id='result'></p>
        </body>
    ">
</frameset>