手动实现v-lazy 

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>v-lazy</title>
</head>
<style>
    .container{
        width: 100%;
        overflow: auto;
        display: flex;
        flex-direction: column;
    }
    .img{
        height: 600px;
        display: block;
    }
</style>
<body>
    <div class="container">
        <img class="img" src="./img/loading.jpg" data-src='./img/1.jpg' alt="img">
        <img class="img" src="./img/loading.jpg" data-src='./img/2.jpg' alt="img">
        <img class="img" src="./img/loading.jpg" data-src='./img/3.jpg'  alt="img">
        <img class="img" src="./img/loading.jpg" data-src='./img/4.jpg'  alt="img">
    </div>
</body>
<script>
    let imgs=document.querySelectorAll('.img');
    let observer=new IntersectionObserver((e,o)=>{
        console.log(e);
        e.map(item=>{
            if(item.intersectionRatio>0){
                item.target.src=item.target.dataset.src;
                observer.unobserve(item.target);
            }
        })
    })
    imgs.forEach(item=>{
        observer.observe(item);
    })
</script>
</html>

参考实现：阮一峰老师：http://www.ruanyifeng.com/blog/2016/11/intersectionobserver_api.html

posted @ 2021-02-20 15:37  榆木脑袋敲啊敲  阅读(102)  评论(0)    收藏  举报