静态网站加速双十一活动

<link rel="stylesheet" href="styles.css?v=1.0.1">
<script src="script.js?v=1.0.1"></script>

<script src="script.js" async></script>
<script src="another-script.js" defer></script>

<img src="thumbnail.jpg" data-src="full-image.jpg" class="lazyload">

document.addEventListener("DOMContentLoaded", function() {
  var lazyImages = [].slice.call(document.querySelectorAll("img.lazyload"));
  if ("IntersectionObserver" in window) {
    let lazyImageObserver = new IntersectionObserver(function(entries, observer) {
      entries.forEach(function(entry) {
        if (entry.isIntersecting) {
          let lazyImage = entry.target;
          lazyImage.src = lazyImage.dataset.src;
          lazyImage.classList.remove("lazyload");
          lazyImageObserver.unobserve(lazyImage);
        }
      });
    });
    lazyImages.forEach(function(lazyImage) {
      lazyImageObserver.observe(lazyImage);
    });
  }
});