<head>
    <script>
        if (window.testRunner)
            testRunner.waitUntilDone();
        function runTest()
        {
            document.getElementById("target").style.backgroundColor = "lightpink";
            if (window.testRunner)
                testRunner.notifyDone();
        }
    </script>
</head>
<body onload="setTimeout(runTest, 0);">
    <button id="target" style="height: 100px; width: 100px; background-color: lightblue; border: none;">&nbsp;</button>
</body>