​x
 
<html>
<head>
<style type="text/css">
body
{
background-color:#FFCC80;
background-image:url(/i/eg_bg_desert.jpg);
}
</style>
<script type="text/javascript">
function changeRepeat()
{
document.body.style.backgroundRepeat="repeat-y";
}
</script>
</head>
​
<body>
​
<input type="button" onclick="changeRepeat()" value="Repeat background-image only on the y-axis" />
​
</body>
</html>
​