https://aqsi.ru/wp-content/themes/aqsi/js/article-menu.js?ver=6.0.2

1$(function(){
2    const target = document.querySelector('#article-menu');
3    if (target) {
4        const
5            output = document.createDocumentFragment(),
6            headers = document.querySelectorAll('.text-block h2, .text-block h3, .text-block h4'),
7            wrapper = document.createElement('div'),
8            title = document.createElement('div'),
9            ol = document.createElement('ul')
10            wrapper.classList.add('article-contents');
11            title.classList.add('article-contents__title');
12            title.classList.add('h4');
13            title.textContent = 'Оглавление:';
14            output.appendChild(wrapper);
15            wrapper.appendChild(title);
16            wrapper.appendChild(ol);
17        ol.classList.add('article-contents__nav');
18        headers.forEach(function(item, index) {
19                const li = document.createElement('li'),
20                    link = document.createElement('a');
21                    
22                    if (item.id === '') {
23                        item.id = 'id-' + index;
24                    }
25
26                    link.setAttribute('data-id', item.id);
27                    link.href = location.href.split('#')[0] + '#' + item.id;
28                    link.textContent = item.textContent;
29                    li.appendChild(link);
30                    ol.appendChild(li);
31            });
32        target.append(output);
33
34        $(document).on('click', '.article-contents li a', function(e) {
35        e.preventDefault();
36        const id = $(this).data('id');
37        $("html, body").animate({
38            scrollTop: $(`#${id}`).offset().top - 100
39        }, {
40            duration: 370,  
41            easing: "linear"
42        });
43    });
44    }
45});