counter

custom.js

'use strict'

const counter = document.getElementById('counter')
let count = 0;

setInterval( () => {
  if ( count <= 1200) {
    counter.innerHTML = count
    count++;
  }
}, .01);

index.html

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>JavaScript Counter</title>
  <meta name="robots" content="noindex, nofollow">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="styles.css">
</head>

<body>
  <header>
    <h1>JavaScript Counter</h1>
  </header>
  <div class="wrapper">
    <div class="container">
      <span id="counter">0</span>
    </div>
    <!-- .container-->
  </div>
  <!-- .wrapper-->
  <footer>
    <small><a href="https://opensource.org/licenses/MIT">MIT</a></small>
  </footer>
  <script src="custom.js"></script>
</body>

</html>

styles.css

body {
  background: #eeeeee;
  font-size: 16px;
  font-family: "Trebuchet MS", Helvetica, sans-serif;
  margin: 0;
}

a {
  color: crimson;
  text-decoration: none;
}

a:hover {
  color: red;
}


/* Layout
------------------------------------------*/

header,
.container,
footer {
  margin: 0 auto;
  width: 88%;
  max-width: 1080px;
}

.wrapper {
  padding: 1em 0;
  background: #ffffff;
}