Add elements

<!DOCTYPE html>
<html>
<body>

<ul id="myList1"><li>Coffee</li><li>Tea</li></ul>
<ul id="myList2"><li>Water</li><li>Milk</li></ul>

<p>Click the button to move an item from one list to another.</p>

<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
  var node = document.getElementById("myList2").lastChild;
  document.getElementById("myList1").appendChild(node);
}
</script>

</body>
</html>