any part of the element is in the viewport

is-any-part-of-element-in-viewport.js

function isAnyPartOfElementInViewport(el) {
  const rect = el.getBoundingClientRect();
  const windowHeight = (window.innerHeight || document.documentElement.clientHeight);
  const windowWidth = (window.innerWidth || document.documentElement.clientWidth);

  const vertInView = (rect.top <= windowHeight) && ((rect.top + rect.height) >= 0);
  const horInView = (rect.left <= windowWidth) && ((rect.left + rect.width) >= 0);

  return (vertInView && horInView);
}