// 图片懒加载
//列：<img class="lazy" data-src="real-image.jpg" src="placeholder.jpg" alt="示例图片">
document.addEventListener("DOMContentLoaded", function() {
    const lazyImages = document.querySelectorAll('.lazy');

    // 检查浏览器是否支持 Intersection Observer
    if ('IntersectionObserver' in window) {
       
        const observer = new IntersectionObserver((entries, observer) => {
           
            entries.forEach(entry => {
                if (entry.isIntersecting) {
                const img = entry.target;
                img.src = img.dataset.src; // 替换真实图片地址
                img.classList.add('loaded'); // 可选：添加加载完成标识
                    observer.unobserve(img); // 停止观察已加载图片
                }
            });
        }, {
            rootMargin: '0px',
            threshold: 0 // 图片进入视口 10% 时触发
        });

        lazyImages.forEach(img => {
            observer.observe(img);
        });
    } else {
        // 兼容旧版浏览器：直接加载所有图片
        lazyImages.forEach(img => {
            mg.src = img.dataset.src;
        });
    }
});