JS实现无缝轮播图原理与代码详解

完整代码示例

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>Document</title>
 <style type="text/css">
 *{padding: 0;margin: 0;}
 .container{
 width: 273px;height: 163px;overflow: hidden;
 position: relative;margin: 0 auto;
 }
 .list{
 position: absolute;width: 1638px;top: 0;left: 0px;
 }
 .list li{
 float: left;list-style: none;
 }
 .btn{
 position: absolute;display: block;width: 40px;height: 50px;font-size: 40px;
 text-align: center;font-weight: bold;top: 50%;margin-top: -25px;background-color: rgba(255,255,255,0.5);cursor:pointer;
 }
 .btn:hover{
 background-color: rgba(0,0,0,0.3);color: #fff;
 }
 .pre{
 left: 0;
 }
 .next{
 right: 0;
 }
 .nav{
 position: absolute;bottom: 5px;display: flex;justify-content: center;width: 100%;
 }
 .nav span{
 width: 10px;height: 10px;border-radius: 10px;background-color: #fff;z-index: 2;display: inline-block;margin-right: 10px;cursor: pointer;
 }
 span.on{
 background-color: orange;
 }
 </style>
</head>
<body>
 <div class="container">
 <ul class="list" style="left: 0px">
 <li><img src="./images/1.png" alt=""></li>
 <li><img src="./images/2.png" alt=""></li>
 <li><img src="./images/3.png" alt=""></li>
 <li><img src="./images/4.png" alt=""></li>
 <li><img src="./images/5.png" alt=""></li>
 <li><img src="./images/1.png" alt=""></li>
 </ul>
 <div class="nav">
 <span class="on"></span>
 <span></span>
 <span></span>
 <span></span>
 <span></span>
 </div>
 <em class="next btn">></em>
 <em class="pre btn"><</em>
 </div>
 <script type="text/javascript" src="../jquery.js"></script>
 <script type="text/javascript">
 $(function(){
 var i=0;
 $('.next').click(function(){
 i++;
 console.log(i);
 
 moveImg(i);
 
 });
 $('.pre').click(function(){
 i--;
 moveImg(i);
 
 });
 $('.nav span').click(function(){
 var _index=$(this).index();
 i=_index;
 moveImg(i);
 
 
 });
 // i的作用：决定下一张图片是谁————也就是说ul的left是多少。
 // $('.list').css({left)的值是从图a过度是此时的ul的left。
 function moveImg(){
 if (i==6) {
 i=1;
 $('.list').css({'left':'0'});
 }
 // 是第一张
 if(i==-1){
 i=4;
 $('ul').css({left:(5*-273)});
 }
 $('.list').stop().animate({'left':-273*i+'px'},1000);
 if (i==5) {
 $('.nav span').eq(0).addClass('on').siblings().removeClass('on');
 
 }
 $('.nav span').eq(i).addClass('on').siblings().removeClass('on');
 
 }
 })
 </script>
</body>
</html>