JavaScript add a Even ,odd class in your listing

sample.js

<ul id="list">
  <li>Item 1</li>
  <li>Item 2</li>
  <li>Item 3</li>
  <li>Item 4</li>
  <li>Item 5</li>
  <li>Item 6</li>
</ul>

<script>
  var IdRef = document.getElementById("list");
  var IdChild = IdRef.getElementByTagName("li");
  for (i=0; i<IdChild.length; i++) {
    if(i%2 == 0) {
      IdChild[i].classList.add('even');
    } else {
      IdChild[i].classList.add('odd');
    }
  }
</script>