<html>
<head>
<script>
function updateColor() {
document.getElementById("updateColorControl").style.backgroundColor = "red";
jsObserver.notifyJava();
}
</script>
<style>
body {
margin: 0px;
padding: 0px;
}
#updateColorControl {
height: 100%;
width: 100%;
padding: 0px 0px;
background-color: blue;
}
</style>
</head>
<body>
<button id="updateColorControl" autofocus onclick="updateColor(); return false"></button>
</body>
</html>