hhh-page-dev/js/index-list.js

let over = document.querySelector('.infoContent .tab-content').offsetHeight+100;
window.addEventListener('scroll', fixedOnOver);
    
const navCollapse = document.querySelector('#nav-collapse');
    
function fixedOnOver() {
    if(window.pageYOffset >= over){
      navCollapse.classList.add('sticky');
    } else {
      navCollapse.classList.remove('sticky');
    }
}