​x
 
<html>
<head>
<script type="text/javascript">
function changeStyle()
{
document.body.style.backgroundColor="#FFCC80";
document.body.style.backgroundImage="url(/i/eg_bg_desert.jpg)";
}
</script>
</head>
<body>
​
<input type="button" onclick="changeStyle()" value="Set background-image" />
​
</body>
</html>
​