手机和pc使用同个域名

<!-- 示例代码：使用Polyfill -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js"></script>

<!-- 示例代码：图片懒加载 -->
<img data-src="image.jpg" class="lazyload" />

<script>
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);
    });
  }
});
</script>

/* 示例代码：媒体查询 */
@media (max-width: 600px) {
  .button {
    font-size: 16px;
    padding: 10px 20px;
  }
}