https://www.highpoint.edu/wp-content/themes/hpu/assets/frontend/scripts/hpu-lazy-load.js?ver=1788398039

1function hpuLazyLoad() {
2	// Exit early if IntersectionObserver is unsupported.
3	if ( ! ( 'IntersectionObserver' in window ) ) {
4		console.log( 'Lazy loading is disabled due to lack of browser support.' );
5		return;
6	}
7
8	function maybeSwapAttribute( element, initial, updated ) {
9		// Exit early if the initial attribute is empty.
10		if ( null === element.getAttribute( initial ) ) {
11			return;
12		}
13
14		// Set the updated attribute to match the value of the initial attribute.
15		element.setAttribute( updated, element.getAttribute( initial ) );
16
17		// Remove the initial attriburte.
18		element.removeAttribute( initial );
19	}
20
21	// Select target elements.
22	const elements           = document.querySelectorAll( 'iframe, img, source' );
23	const excluded           = [ 'skip-lazy', 'simple-parallax' ];
24	const excludedContainers = [ 'foo-table' ];
25
26	// Define the observer options.
27	const observerOptions = {
28		root:       null,       // default is viewport
29		rootMargin: '400px 0px' // intersection buffer (CSS style margin rule, MUST include `px` or `%`, even if 0)
30	};
31
32	// Initialize the intersection observer.
33	const observer = new IntersectionObserver( ( entries ) => {
34		entries.forEach( entry => {
35			// Set the target element.
36			const element = entry.target;
37
38			if ( entry.isIntersecting ) {
39				// Manipulate intersecting element to trigger loading.
40				maybeSwapAttribute( element, 'data-src', 'src' );
41				maybeSwapAttribute( element, 'data-srcset', 'srcset' );
42
43				// Stop observing intersecting element.
44				observer.unobserve( element );
45			}
46			else {
47				// Manipulate non-intersecting element to prevent early loading.
48				maybeSwapAttribute( element, 'src', 'data-src' );
49				maybeSwapAttribute( element, 'srcset', 'data-srcset' );
50			}
51		} );
52	}, observerOptions );
53
54	elements.forEach( element => {
55		// Exit early if the element classList contains any excluded classes.
56		if ( excluded.some( className => element.classList.contains( className ) ) ) {
57			return;
58		}
59
60		// Exit early if the element is inside an excluded container
61		if ( excludedContainers.some( className => element.closest( '.' + className ) ) ) {
62			return;
63		}
64
65		observer.observe( element );
66	} );
67}
68
69// Trigger lazy load on page load event.
70window.addEventListener( 'DOMContentLoaded', hpuLazyLoad );