CODE EXAMPLE FOR JAVASCRIPT

how to check if element is in viewport javascript

function elementInViewport(el) {
  let top = el.offsetTop;
  let left = el.offsetLeft;
  let width = el.offsetWidth;
  let height = el.offsetHeight;

  while(el.offsetParent) {
    el = el.offsetParent;
    top += el.offsetTop;
    left += el.offsetLeft;
  }

  return (
    top >= window.pageYOffset &&
    left >= window.pageXOffset &&
    (top + height) <= (window.pageYOffset + window.innerHeight) &&
    (left + width) <= (window.pageXOffset + window.innerWidth)
  );
}