jQuery(document).ready(function($) { // create new observer with the trigger point when the element is 25% visible let observer = new IntersectionObserver( isElScrolledIntoView, { root: null, rootMargin: '0px', threshold: 0.25 }); // grab elements by global class const elements = document.querySelectorAll('.product-section'); // loop over all elements and observe each of them elements.forEach( element => { observer.observe(element); }); // create function to perform action on each observed element function isElScrolledIntoView( entries ) { // again loop over all entries (element) entries.forEach( entry => { // check if the entry is intersecting at our set threshold if ( entry.isIntersecting ) { // set a class to toggle animation entry.target.classList.add('view-animation'); } else { // if we've stopped intersecting, let's remove the animation entry.target.classList.remove('view-animation'); } }); } })