偶然间看到微信公众号推送的关于js实现下拉、上拉的文章，测试后赶紧效果不错，稍作修改，呈现给大家。
实现效果
hc3fs-hogeq.gif
示例代码
<!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>弹动效果 touch.js</title>
<style>
*{
margin: 0;
padding: 0;
}
html, body{
width: 100%;
}
.app {
width: 100%;
height: 100%;
}
/* 列表的父盒子，限制宽高 */
/* 注意设置overflow: hidden;样式后，超出这个盒子的ul将不会显示 */
.draw {
width: 100%;
height: 100%;
border: 2px solid #ccc;
overflow: hidden;
position: fixed;
/* top: 50%;
transform: translateY(-50%); */
}
/* li 设置了浮动， 所以 ul 要清除浮动 */
ul {
zoom: 1;
padding: 0 10%;
}
ul::after {
content: "";
display:block;
visibility: hidden;
height: 0;
clear: both;
}
li {
list-style: none;
float: left;
width:100px;
height:100px;
line-height:100px;
text-align: center;
}
</style>
</head>
<body>
<div class="app">
<div class="draw" id="draw">
<ul>
<li style="background:orange"></li>
<li style="background:cyan"></li>
<li style="background:orange"></li>
<li style="background:olivedrab"></li>
<li style="background:purple"></li>
<li style="background:cornflowerblue"></li>
</ul>
</div>
</div>
<script>
var startY = 0;
const maxMove = 500;
var draw = document.getElementById('draw');
var ul = draw.children[0];
draw.addEventListener('touchstart', function(event) {
console.log('%ctouchstart // clientY: '+event.changedTouches[0].clientY,"color:green");
startY = event.changedTouches[0].clientY;
});
draw.addEventListener('touchmove', function(event) {
console.log('touchmove // clientY: '+event.changedTouches[0].clientY);
const y = event.changedTouches[0].clientY - startY <= maxMove ? event.changedTouches[0].clientY - startY : maxMove;
// 为了清除卡顿问题，需要清除过渡效果
ul.style.transition = "none";
// 阻尼系数0.3
ul.style.transform = 'translateY('+0.3*y+'px)';
});
draw.addEventListener('touchend', function(event) {
console.log('%ctouchend // clientY: '+event.changedTouches[0].clientY,"color:orange");
const y = event.changedTouches[0].clientY - startY;
// 添加过渡效果
ul.style.transition = 'transform .6s';
ul.style.transform = 'translateY('+0+'px)';
});
</script>
</body>
</html>
