<!DOCTYPE html>
<html>
<body>

<ul id="myList">
  <li id="myLI">Coffee</li>
</ul>

<p>Click one button to remove the li element from ul. Click the other button to insert the removed li element to ul.</p>

<button onclick="removeLi()">Remove li</button>
<button onclick="appendLi()">Insert li</button>

<script>
var item = document.getElementById("myLI");

function removeLi() {
    item.parentNode.removeChild(item);
}

function appendLi() {
    var list = document.getElementById("myList");
    list.appendChild(item);
}
</script>

</body>
</html>