<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
* {
margin: 0;
padding: 0;
}
ul {
overflow: hidden;
}
li {
list-style: none;
width: 600px;
height: 460px;
border: 1px solid #ccc;
box-sizing: border-box;
-webkit-box-sizing: border-box;
float: left;
overflow: hidden;
position: relative;
}
li i {
width: 20px;
height: 20px;
border-radius: 20px;
position: absolute;
border: 2px solid #6feb95;
z-index: 0;
left: 50%;
top: 50%;
margin-top: -11px;
margin-left: -11px;
animation: move 1s infinite;
-webkit-animation: move 1s infinite;
}
li i:before {
position: absolute;
width: 5px;
height: 5px;
border-radius: 4px;
content: '';
box-shadow: 0 0 10px #666;
-webkit-box-shadow: 0 0 10px #666;
background: #fff;
border: 1px solid #fff;
top: -3px;
left: 50%;
margin-left: -3px;
}
img {
vertical-align: middle;
border-width: 0;
width: 100%;
position: relative;
z-index: 1;
}
@keyframes move {
0% {
transform: rotateZ(0);
}
100% {
transform: rotateZ(360deg);
}
}
@-webkit-keyframes move {
0% {
-webkit-transform: rotateZ(0);
}
100% {
-webkit-transform: rotateZ(360deg);
}
}
</style>
</head>
<body>
<ul>
<li data-src="http://pic.58pic.com/58pic/17/18/97/01U58PIC4Xr_1024.jpg"><i></i></li>
<li data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p01N203pHTU7/Wr5314kcLAtVCi.jpg!t"><i></i></li>
<li data-src="http://77fkxu.com1.z0.glb.clouddn.com/20160308/1457402219_73571.jpg"><i></i></li>
<li data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p01a3SXHo2hZ/XYAC5TLk4uYWXn.jpg!t"><i></i></li>
<li data-src="http://pic1.cxtuku.com/00/16/18/b3809a2ba0f3.jpg"><i></i></li>
<li data-src="http://img.bitscn.com/upimg/allimg/c150708/14363B06253120-6060O.jpg"><i></i></li>
<li data-src="http://pic.58pic.com/58pic/17/18/97/01U58PIC4Xr_1024.jpg"><i></i></li>
<li data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p015trgKM7vw/H0iyDPPneOVrA4.jpg!t"><i></i></li>
<li data-src="http://77fkxu.com1.z0.glb.clouddn.com/20160308/1457402219_73571.jpg"><i></i></li>
<li data-src="http://imgsrc.baidu.com/baike/pic/item/2f9cbdcc5e0bcf5c00e9283b.jpg"><i></i></li>
<li data-src="http://pic1.cxtuku.com/00/16/18/b3809a2ba0f3.jpg"><i></i></li>
<li data-src="http://img.bitscn.com/upimg/allimg/c150708/14363B06253120-6060O.jpg"><i></i></li>
<li data-src="http://pic.58pic.com/58pic/17/18/97/01U58PIC4Xr_1024.jpg"><i></i></li>
<li data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p015trgKM7vw/H0iyDPPneOVrA4.jpg!t"><i></i></li>
<li data-src="http://77fkxu.com1.z0.glb.clouddn.com/20160308/1457402219_73571.jpg"><i></i></li>
<li data-src="http://imgsrc.baidu.com/baike/pic/item/2f9cbdcc5e0bcf5c00e9283b.jpg"><i></i></li>
<li data-src="http://pic1.cxtuku.com/00/16/18/b3809a2ba0f3.jpg"><i></i></li>
<li data-src="http://img.bitscn.com/upimg/allimg/c150708/14363B06253120-6060O.jpg"><i></i></li>
<li data-src="http://pic.58pic.com/58pic/17/18/97/01U58PIC4Xr_1024.jpg"><i></i></li>
<li data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p015trgKM7vw/H0iyDPPneOVrA4.jpg!t"><i></i></li>
<li data-src="http://77fkxu.com1.z0.glb.clouddn.com/20160308/1457402219_73571.jpg"><i></i></li>
<li data-src="http://imgsrc.baidu.com/baike/pic/item/2f9cbdcc5e0bcf5c00e9283b.jpg"><i></i></li>
<li data-src="http://pic1.cxtuku.com/00/16/18/b3809a2ba0f3.jpg"><i></i></li>
<li data-src="http://img.bitscn.com/upimg/allimg/c150708/14363B06253120-6060O.jpg"><i></i></li>
<li data-src="http://pic.58pic.com/58pic/17/18/97/01U58PIC4Xr_1024.jpg"><i></i></li>
<li data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p015trgKM7vw/H0iyDPPneOVrA4.jpg!t"><i></i></li>
<li data-src="http://77fkxu.com1.z0.glb.clouddn.com/20160308/1457402219_73571.jpg"><i></i></li>
<li data-src="http://imgsrc.baidu.com/baike/pic/item/2f9cbdcc5e0bcf5c00e9283b.jpg"><i></i></li>
<li data-src="http://pic1.cxtuku.com/00/16/18/b3809a2ba0f3.jpg"><i></i></li>
<li data-src="http://img.bitscn.com/upimg/allimg/c150708/14363B06253120-6060O.jpg"><i></i></li>
<li data-src="http://pic.58pic.com/58pic/17/18/97/01U58PIC4Xr_1024.jpg"><i></i></li>
<li data-src="http://cover.read.duokan.com/mfsv2/download/fdsc3/p015trgKM7vw/H0iyDPPneOVrA4.jpg!t"><i></i></li>
<li data-src="http://77fkxu.com1.z0.glb.clouddn.com/20160308/1457402219_73571.jpg"><i></i></li>
<li data-src="http://imgsrc.baidu.com/baike/pic/item/2f9cbdcc5e0bcf5c00e9283b.jpg"><i></i></li>
<li data-src="http://pic1.cxtuku.com/00/16/18/b3809a2ba0f3.jpg"><i></i></li>
<li data-src="http://img.bitscn.com/upimg/allimg/c150708/14363B06253120-6060O.jpg"><i></i></li>
</ul>
<script type="text/javascript">
/* 获取节点 */
var oUl = document.getElementsByTagName('ul')[0];
var aLi = oUl.getElementsByTagName('li');
/* 创建img标签函数 */
function createImg(obj) {
var src = '';
if(obj.dataset.src) {
src = obj.dataset.src;
} else {
src = obj.getAttribute('data-src');
}
if(obj.children.length <= 1) {
var img = document.createElement('img');
img.src = src;
obj.appendChild(img);
}
}
/* 计算节点到文档顶部的距离 */
function getTop(obj) {
var h = 0;
while(obj) {
h += obj.offsetTop;
obj = obj.offsetParent;
}
return h;
}
/* 滚动实时计算所到区域并进行相关计算 */
window.onscroll = function() {
var t = document.documentElement.clientHeight + (document.body.scrollTop || document.documentElement.scrollTop);
for(var i = 0; i < aLi.length; i++) {
if(getTop(aLi[i]) < t) {
setTimeout('createImg(aLi[' + i + '])', 500)
}
}
}
/* 页面加载完便执行一次滚动函数 */
window.onload = function() {
window.onscroll();
}
</script>
</body>
</html>
转：https://www.jianshu.com/p/4f6ea540516a