<!DOCTYPE html>
<html>
<body>
    <math>
        <mrow>
            <mo id="test1" stretchy="false">&Integral;</mo>
            <mspace height="75px" depth="1px"/>
        </mrow>
    </math>

    <script>
        if (window.testRunner)
            testRunner.waitUntilDone();

        function updatePageAfterRendering()
        {
            setTimeout(function()
                {
                    document.getElementById("test1").setAttribute("stretchy", "true");
                    testRunner.notifyDone();
                }, 50);
        }

        addEventListener('load', updatePageAfterRendering, false);

    </script>
</body>
</html>