[danik.js]

<ul id="ul"></ul>
<script>
var items = ['111', '222', '333'];
var node = document.getElementById('ul');

for (var key in items) {
  var item = document.createElement('li');
  item.textContent = items[key];
  node.insertBefore(item, node.firstChild);
}
</script>

<ul id="ul"></ul>
<script>
var items = ['111', '222', '333'];
var node = document.getElementById('ul');

for (var key in items) {
  var item = document.createElement('li');
  item.textContent = items[key];
  node.appendChild(item);
}
</script>

Что именно не ясно?