思路只要是ul移动前，首先将当前显示的li克隆岛ul最后，当每次运动执行完毕后，再将前面的li删除，如此循环。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Examples</title>
<meta name="description" content="">
<meta name="keywords" content="">
<link href="" rel="stylesheet">
</head>
<style type="text/css">
.wrap{
320px;
height:50px;
overflow: hidden;
margin:0 auto;
margin-top:50px;
position: relative;
border:1px solid #333;
}
.wrap ul{
position: absolute;
overflow: hidden;
padding:0px;
margin:0;
/*这个属性很重要，moveStart需要获取到*/
left:0px;
}
.wrap ul li{
100px;
height:50px;
float: left;
line-height: 50px;
text-align:center;
background:orange;
font-size: 16px;
margin-right: 10px;
color:#fff;
list-style-type: none;
}
</style>
<body>
<input type="button" value ="我要切" id="tab">
<div class="wrap" id="wrap">
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
</ul>
</div>
</body>
</html>
<script type="text/javascript" src="startMove.js"></script>
js
<script type="text/javascript">
window.onload = function(){
var iNum = 3;
var oBtn = document.getElementById('tab');
var timer;
var wrap = document.getElementById('wrap');
var oUl = wrap.getElementsByTagName('ul')[0];
var b = true;
var aLi = oUl.getElementsByTagName('li');
//获取每个单位的宽度包括li的宽度和margin
var oSize = parseInt(getStyle(aLi[0],'marginRight')) + parseInt(getStyle(aLi[0],'width'));
//设置ul的宽度
function getWidth(){
oUl.style.width = aLi.length * oSize +'px';
}
getWidth();
//移动函数
function slider(){
//防止连续点击切换bug
if(b){
//在运动函数没有结束之前，b为false，点击无效
b=false;
for (i = 0; i< iNum ;i++){
//复制iNum个li
var oLi = aLi[i].cloneNode(true);
//移动到ul最后
oUl.appendChild(oLi);
//重新设置宽度
getWidth();
}
//运动函数startMove(obj,json,fn)
startMove(
//当前对象
oUl,
//移动距离
{left : -iNum * oSize},
//回调
function(){
for( i = 0; i< iNum ; i++){
//移除第一个li
oUl.removeChild(aLi[0]);
//设置ul的left为0
oUl.style.left = 0 +'px';
}
//运动结束，b为true，可以继续下一次点击
b=true;
}
);
}
};
//触发
oBtn.onclick = function(){
if(t){
clearInterval(t);
}
slider();
};
//自动播放
function autoPlay(t){
timer = setInterval(slider,t);
}
autoPlay(3000)
};
</script>
startMove.js
function startMove(obj, json, fn) {
clearInterval(obj.timer);
obj.timer = setInterval(function() {
var bStop = true;
for (attr in json) {
var icur = 0;
icur = (attr == 'opacity') ? Math.round(getStyle(obj, attr) * 100) : parseInt(getStyle(obj, attr));
var iSpeed = (json[attr] - icur) / 8;
iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);
if (icur != json[attr]) {
bStop = false;
}
if (attr == 'opacity') {
obj.style.filter = 'alpha(opacity:' + (icur + iSpeed) + ')';
obj.style.opacity = (icur + iSpeed) / 100;
} else {
obj.style[attr] = icur + iSpeed + 'px';
}
}
if (bStop) {
clearInterval(obj.timer);
if (fn) {
fn();
}
}
}, 30);
}
function getStyle(obj, attr) {
if (obj.currentStyle) {
return obj.currentStyle[attr];
} else {
return getComputedStyle(obj, false)[attr];
}
}