Avoid paints on scroll. Source: http://www.thecssninja.com/javascript/pointer-events-60fps . Instead of document.body you might want to use document.documentElement if you're using html adn body as a free div.

scroll-painting

CSS
.disable-hover {
  pointer-events: none;
}

JS
var body = document.body,
    timer;

window.addEventListener('scroll', function() {
  clearTimeout(timer);
  if(!body.classList.contains('disable-hover')) {
    body.classList.add('disable-hover')
  }
  
  timer = setTimeout(function(){
    body.classList.remove('disable-hover')
  },500);
}, false);


OR


CSS
.scroll-cover {
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  position: fixed;
  pointer-events: auto !important;
  z-index: 10000;
}

JS
var body = document.body,
    cover = document.createElement('div');
    cover.setAttribute('class','scroll-cover');

window.addEventListener('scroll', function() {
  clearTimeout(timer);
  body.appendChild(cover);
  
  timer = setTimeout(function(){
    body.removeChild(cover);
  },500);
}, false);