https://www.pnnl.gov/themes/gesso/js/homepage.js?v=9.5.11

1(function($) {
2
3  /**
4   * Copyright 2012, Digital Fusion
5   * Licensed under the MIT license.
6   * http://teamdf.com/jquery-plugins/license/
7   *
8   * @author Sam Sehnert
9   * @desc A small plugin that checks whether elements are within
10   *     the user visible viewport of a web browser.
11   *     only accounts for vertical position, not horizontal.
12   */
13
14  $.fn.visible = function(partial) {
15
16    var $t = $(this),
17      $w = $(window),
18      viewTop = $w.scrollTop(),
19      viewBottom = viewTop + $w.height(),
20      _top = $t.offset().top,
21      _bottom = _top + $t.height(),
22      compareTop = partial === true ? _bottom : _top,
23      compareBottom = partial === true ? _top : _bottom;
24
25    return ((compareBottom <= viewBottom) && (compareTop >= viewTop));
26
27  };
28
29})(jQuery);
30
31(function ($, Drupal) {
32
33  'use strict';
34
35  Drupal.behaviors.homepageAnimation = {
36    attach: function (context) {
37      const homepage = $('.l-homepage-2', context);
38      if (!homepage || homepage.length < 1) return;
39      const win = $(window);
40      const allMods = $(
41        ".paragraph--type-compound-featured-card-grid .l-grid > .paragraph," +
42        ".paragraph--type-compound-featured-card-grid .l-section__title," +
43        ".paragraph--type-compound-blockquote-grid .l-grid > .field .field__item > .paragraph," +
44        ".paragraph--type-compound-blockquote-grid .l-section__title," +
45        ".sign-up-bar," +
46        ".banner-bar," +
47        ".icon-bar," +
48        ".layout--twocol > .l-section__content," +
49        ".paragraph--type-simple-headline",
50        homepage
51      );
52
53      allMods.each(function(i, el) {
54        const $el = $(el);
55        if ($el.visible(true)) {
56          $el.addClass("already-visible");
57        }
58      });
59
60      win.scroll(function(event) {
61        allMods.each(function(i, el) {
62          const $el = $(el);
63          if ($el.visible(true)) {
64            $el.addClass("come-in");
65          }
66        });
67      });
68    }
69  }
70
71})(jQuery, Drupal);