图片懒加载

最新推荐文章于 2025-06-13 11:21:22 发布

原创最新推荐文章于 2025-06-13 11:21:22 发布 · 137 阅读

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本文介绍了一种网页中图片懒加载的实现方式，通过监听滚动事件动态加载图片，以提高网页加载速度和用户体验。该方法利用JavaScript遍历图片元素，当图片进入可视区域时才加载其真实地址。

	  <style>
	        img {
	            display: block;
	            margin-bottom: 50px;
	            width: 800px;
	            height: 400px;
	        }
	    </style>
	</head>
	<body>
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg6.png" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg7.png" alt="">
	    <img src="" data-src="http://ww1.sinaimg.cn/large/006y8mN6gw1fa7kaed2hpj30sg0l9q54.jpg" alt="">
	    <img src="" data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p01N203pHTU7/Wr5314kcLAtVCi.jpg!t" alt="">
	    <img src="" data-src="http://77fkxu.com1.z0.glb.clouddn.com/20160308/1457402219_73571.jpg" alt="">
	    <img src="" data-src="http://pic1.cxtuku.com/00/16/18/b3809a2ba0f3.jpg" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg9.png" alt="">
	    <img src="" data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p015trgKM7vw/H0iyDPPneOVrA4.jpg!t" alt="">
	    <img src="" data-src="http://ww1.sinaimg.cn/large/006y8mN6gw1fa7kaed2hpj30sg0l9q54.jpg" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg8.png" alt="">
	    <img src="" data-src="http://ww4.sinaimg.cn/large/006y8mN6gw1fa5obmqrmvj305k05k3yh.jpg" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg9.png" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg10.png" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg11.png" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg15.png" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg16.png" alt="">
	    <img src="" data-src="https://www.mwcxs.top/static/staticImage/sliders/bg17.png" alt="">
	<script>
	    (function(){
	    let num = document.getElementsByTagName('img').length;
	    let img = document.getElementsByTagName("img");
	    let n = 0; //存储图片加载到的位置，避免每次都从第一张图片开始遍历
	    lazyload(); //页面载入完毕加载可是区域内的图片
	     window.onscroll = lazyload;
	    function lazyload() { //监听页面滚动事件
	        let seeHeight = document.documentElement.clientHeight; //可见区域高度
	        let scrollTop = document.documentElement.scrollTop || document.body.scrollTop; //滚动条距离顶部高度
	        for (let i = n; i < num; i++) {
	            // 图片未出现时距离顶部的距离大于滚动条距顶部的距离+可视区的高度
	            if (img[i].offsetTop<= seeHeight + scrollTop) {
	                if (img[i].getAttribute("src") == "") {
	                    img[i].src = img[i].getAttribute("data-src");
	                }
	                n = i + 1;
	            }
	        }
	    }
	    })()
	
	</script>