<div id="list">
  <h2>Animals</h2>
</div>
html, body {
  height: 100%;
}

body {
  display: grid;
  justify-content: center;
  align-content: center;
}
const animals = ['cat', 'dog', 'mouse', 'cow', 'horse', 'duck']
const items = []

for (const animal of animals) {
  items.push(`<li>${animal}</li>`)
}

const list = `
<ul>
  ${items.join('')}
</ul>`

const $list = document.getElementById('list')
$list.innerHTML = $list.innerHTML + list

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.