How to Create a Scroll Indicator with JavaScript

Have you noticed that when you scroll the webpage there is a scrollbar at the top of the page?

This indicator shows how far the page has been scrolled. Scroll position indicators have different forms: variations on the vertical scrollbar, horizontal elements at the top or bottom of the page, and other styles.

In this snippet, we are going to show a simple and quick way to create a scroll indicator for your website with the help of a little JavaScript code.

Use the onscroll event on the window object so that the indicator updates only when the user scrolls the page:

Javascript scroll indicator

javascript

window.onscroll = function () {
  let windowScroll = document.documentElement.scrollTop;
  let windowHeight = document.documentElement.scrollHeight - document.documentElement.clientHeight;
  let scrollAmount = (windowScroll / windowHeight) * 100;
  document.getElementById("mybar").style.width = scrollAmount + "%";
};

The example of scroll indicator created with JavaScript:

Javascript scroll indicator

html

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      .header {
        position: fixed;
        top: 0;
        z-index: 1;
        width: 100%;
        background-color: #32a2a8;
      }
      .header h2 {
        text-align: center;
      }
      .container {
        width: 100%;
        height: 10px;
        background: #ccc;
      }
      .progress-bar {
        height: 10px;
        background: #005357;
        width: 0%;
      }
      .text {
        padding: 100px 0;
      }
    </style>
  </head>
  <body>
    <div class="header">
      <h2>Scroll Indicator</h2>
      <div class="container">
        <div class="progress-bar" id="mybar"></div>
      </div>
    </div>
    <div class="text">
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
      <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
    </div>
    <script>
      window.onscroll = function() {
        let windowScroll = document.documentElement.scrollTop;
        let windowHeight = document.documentElement.scrollHeight - document.documentElement.clientHeight;
        let scrollAmount = (windowScroll / windowHeight) * 100;
        document.getElementById("mybar").style.width = scrollAmount + "%";
      };
    </script>
  </body>
</html>

How to Create a Scroll Indicator with JavaScript ​

How to Create a Scroll Indicator with JavaScript