window.IntersectionObserver code example

Example 1: IntersectionObserver

var options = {
  root: document.querySelector('#scrollArea'),
  rootMargin: '0px',
  threshold: 1.0
}

var observer = new IntersectionObserver(callback, options);

Example 2: intersection observer example

const images = document.querySelectorAll('.lazyload');

function handleIntersection(entries) {
  entries.map((entry) => {
    if (entry.isIntersecting) {
      entry.target.src = entry.target.dataset.src;
      entry.target.classList.add('loaded')
      observer.unobserve(entry.target);
    }
  });
}

const observer = new IntersectionObserver(handleIntersection);

images.forEach(image => observer.observe(image));