JSFiddle - React, Tailwind, and code Playground

by Artem

HTML

<div class="progress"><div></div></div>
<p>Scroll me...</p>
<script>
  var bar = document.querySelector(".progress div");
  addEventListener("scroll", function() {
    var max = document.body.scrollHeight - innerHeight;
    var percent = (pageYOffset / max) * 100;
    bar.style.width = percent + "%";
  });
</script>

CSS

.progress {
    border: 1px solid blue;
    width: 100px;
    position: fixed;
    top: 10px; right: 10px;
  }
  .progress > div {
    height: 12px;
    background: blue;
    width: 0%;
  }
  body {
    height: 2000px;