<html><head>
<style>
body {
background-color: red;
background-image: url('http://dl.dropbox.com/u/6001712/javascript.ru/bg.png')}
</style>
</head><body>
<button onclick="document.body.style.backgroundColor = 'red'">Red</button>
<button onclick="document.body.style.backgroundColor = 'green'">Green</button>
<button onclick="document.body.style.backgroundColor = 'blue'">Blue</button>
</body></html>