双11图片瘦身选购

<!-- 使用srcset属性根据屏幕分辨率提供不同大小的图片 -->
<img src="small.jpg"
     srcset="medium.jpg 1000w, large.jpg 2000w"
     sizes="(max-width: 600px) 480px, 800px"
     alt="商品图片">

// 使用JavaScript进行图片懒加载
document.addEventListener("DOMContentLoaded", function() {
    let lazyImages = [].slice.call(document.querySelectorAll("img.lazy"));
    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("lazy");
                    lazyImageObserver.unobserve(lazyImage);
                }
            });
        });
        lazyImages.forEach(function(lazyImage) {
            lazyImageObserver.observe(lazyImage);
        });
    }
});