<!DOCTYPE html>
<html>
<body>
<ul id="myList">
<li>Coffee</li>
<li>Tea</li>
<li>Water</li>
<li>Soda</li>
</ul>
<button type="button" onclick="myFunction()">Change list style</button>
<script>
function myFunction() {
document.getElementById("myList").style.listStyle = "decimal inside";
}
</script>
</body>
</html>