On-scroll animations are one of the most popular and enduring web-development techniques from recent years. With them, HTML elements remain hidden until the user scrolls the page, whereupon the element reveals itself with an impressive animation that makes your site look dynamic and modern, unlike the static pages in the past.
We are using the popular scrollReveal.js script for the onscroll animation feature. You can find all the details and the information you might need on their website.
You can see the scrollReveal.js demo here.