<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
* {
margin: 0;
padding: 0;
}
#warp {
width: 800px;
margin: 0 auto;
border: 1px solid red;
}
ul {
list-style: none;
float: left;
width: 198px;
}
.oli {
width: 100%;
height: 198px;
background: blue;
border: 1px solid yellow;
font-size: 100px;
color: #fff;
text-align: center;
}
</style>
</head>
<body>
<div id="warp">
<ul></ul>
<ul></ul>
<ul></ul>
<ul></ul>
</div>
</body>
<script type="text/javascript">
var oul = document.getElementsByTagName('ul');
var n = 1;
function random(min, max) {
return parseInt(Math.random() * (max - min)) + min;
}
function caeta() {
for (var i = 0; i < 20; i++) {
//大的循环里面分为3部分
//1部分代码的主要作用 是创建li标签，并且给li标签添加样式，添加序号
var oli = document.createElement('li');
oli.setAttribute('class', 'oli');
oli.innerHTML = n++;
oli.style.height=random(100,400)+'px'
oli.style.backgroundImage = 'url(images/' + i + '.jpg)';
oli.style.backgroundPosition = '40% 50%';
//2创建一个空数组，循环吧所有ul的高度放入到数组里面去
var arr = []; //arr=[198,0,0,0]
for (var j = 0; j < oul.length; j++) {
arr.push(oul[j].offsetHeight);
}
// console.log(arr)
var minH = arr[0]; //minH=198
//3这么给所有ul分陪创建好的li标签
var index = 0;
//循环ul的长度
for (var k = 0; k < oul.length; k++) {
//让minH的值和所有ul的值进行比较
if (minH > oul[k].offsetHeight) {
minH = oul[k].offsetHeight;
index = k;
}
}
oul[index].appendChild(oli);
}
}
caeta()
window.onscroll = function() {
//获取滚动条的值
var h = document.documentElement.scrollTop || document.body.scrollTop;
//获取可视区域的高度值
var clienH = document.documentElement.clientHeight;
//获取页面的高度值
var pageH = document.documentElement.offsetHeight;
// console.log(pageH)//1002
// console.log(clienH)//969
// console.log(h)//33
if (h >= (pageH - clienH)) {
caeta();
}
}
</script>
</html>
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