时间:2021-07-01 10:21:17 帮助过:11人阅读
API:
https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API
直接上源码:
- <!DOCTYPE html>
- <html>
- <header>
- <style>
- .list-item{
- height: 400px;
- margin: 5px;
- background-color: lightblue;
- list-style: none;
- }
- </style>
- </header>
- <body>
- <li class="list-item"><img class="list-item-img" alt="loading" data-src='./images/icon1.png'></li>
- <li class="list-item"><img class="list-item-img" alt="loading" data-src='./images/icon2.png'></li>
- <li class="list-item"><img class="list-item-img" alt="loading" data-src='./images/icon3.png'></li>
- <li class="list-item"><img class="list-item-img" alt="loading" data-src='./images/icon4.png'></li>
- <li class="list-item"><img class="list-item-img" alt="loading" data-src='./images/icon5.png'></li>
- <li class="list-item"><img class="list-item-img" alt="loading" data-src='./images/icon6.png'></li>
- <script>
- var observer = new IntersectionObserver(function(changes) {
- console.log(changes);
- changes.forEach(function(element, index) {
- // statements
- if (element.intersectionRatio > 0 && element.intersectionRatio <= 1) {
- element.target.src = element.target.dataset.src;
- }
- });
- });
- function addObserver() {
- var listItems = document.querySelectorAll('.list-item-img');
- listItems.forEach(function(item) {
- observer.observe(item);
- });
- }
- addObserver();
- </script>
- </body>
- </html>
运行代码后发现,当滚动滚动轴时,只有当<li>区域完全显示出来后才会触发相应的下载图片的http请求。
兼容浏览器:
desktop:
Mobile:
以上这篇IntersectionObserver实现图片懒加载的示例就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持脚本之家。