<html>
<head>
<script type="text/javascript">
function changeList()
{
document.getElementById("ul1").style.listStyleImage="url('/i/ct_blueball.gif')";
}
</script>
</head>
<body>
<ul id="ul1">
<li>Coffee</li>
<li>Tea</li>
<li>Water</li>
<li>Soda</li>
</ul>
<input type="button" onclick="changeList()" value="Change list-item marker" />
</body>
</html>