https://mslinn.com/assets/js/scroll_more.js

1document.addEventListener('DOMContentLoaded', function() {
2  document.querySelectorAll('.maxOneScreenHigh').forEach(el => {
3    function updateScrollState() {
4      const hasOverflow = el.scrollHeight > el.clientHeight;
5      const isAtBottom = Math.abs(el.scrollHeight - el.clientHeight - el.scrollTop) < 1;
6      const isScrolledFromTop = el.scrollTop > 1;
7
8      el.classList.toggle('has-overflow', hasOverflow);
9      el.classList.toggle('scrolled-to-bottom', isAtBottom);
10      el.classList.toggle('scrolled-from-top', isScrolledFromTop);
11    }
12
13    updateScrollState();
14    el.addEventListener('scroll', updateScrollState);
15    window.addEventListener('resize', updateScrollState);
16  });
17});