https://nbmbaa.org/wp-content/themes/thegem/js/thegem-ken-burns.js?ver=5.12.3.1

1document.addEventListener('DOMContentLoaded', function() {
2    const items = document.querySelectorAll('.thegem-ken-burns-bg');
3
4    if ('IntersectionObserver' in window) {
5        let intersectionObserver = new IntersectionObserver(function(entries, imgObserver) {
6            entries.forEach(function(entry) {
7                const item = entry.target;
8
9                if (entry.isIntersecting) {
10                    item.classList.add('thegem-ken-burns-inited');
11                } else {
12                    item.classList.remove('thegem-ken-burns-inited');
13                }
14            });
15        });
16
17        items.forEach(function(item) {
18            intersectionObserver.observe(item);
19        });
20    } else {
21        items.forEach(function(item) {
22            item.classList.add('thegem-ken-burns-inited');
23        });
24    }
25});