https://www.jynarque.com/sites/g/files/qhldwo12166/themes/site/the…/assets/build/js/base/focus.js

1"use strict";
2
3function customRules(element) {
4  return !(element.classList.contains('interstitial-minified') || element.classList.contains('interstitial-learn-more') || element.classList.contains('interstitial-collapse'));
5}
6
7function isClicking() {
8  document.body.classList.add('user-is-clicking');
9  document.body.classList.remove('user-is-tabbing');
10}
11
12function isTabbing(e) {
13  var keyCode = e.keyCode || e.which;
14
15  if (keyCode === 9) {
16    document.body.classList.add('user-is-tabbing');
17    document.body.classList.remove('user-is-clicking');
18  }
19}
20
21document.onmousedown = isClicking;
22document.onkeydown = isTabbing;
23var previousElementOffsetTop = 0;
24
25Element.prototype.documentOffsetTop = function () {
26  return this.offsetTop + (this.offsetParent ? this.offsetParent.documentOffsetTop() : 0);
27};
28
29Element.prototype.scrollIntoCustomPosition = function () {
30  if (customRules(document.activeElement)) {
31    var documentOffsetTop = this.documentOffsetTop();
32    var elementOffsetHeight = document.activeElement.offsetHeight;
33    var resultPosition = documentOffsetTop - window.innerHeight / 2 + elementOffsetHeight / 2;
34
35    if (Math.abs(previousElementOffsetTop - documentOffsetTop) > 100 || elementOffsetHeight > 100) {
36      window.scrollTo(0, resultPosition);
37      previousElementOffsetTop = documentOffsetTop;
38    }
39  }
40};
41
42function jumpFocusAlt(e) {
43  var keyCode = e.keyCode || e.which;
44
45  if (keyCode === 9) {
46    if (document.body.classList.contains('user-is-tabbing')) {
47      document.activeElement.scrollIntoCustomPosition();
48    }
49  }
50}
51
52window.addEventListener('keyup', jumpFocusAlt);