原生Js 实现的简单无缝滚动轮播图

原简单的滚动轮播代码

 

<html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .scroll{
            position: relative;
            width: 830px;/*展示宽度 展示4个图+3个边框=830*/
            height: 130px;
            border: 10px solid rgb(15, 15, 15);
            margin: 100px auto;
            overflow: hidden;
        }
        .scroll ul{
            position: absolute;
            width: 5000px;/*ul能存下所有li的宽*/
            height: 130px;
            top: 0;
            left: 0;
        }
        .scroll ul li{
            float: left;
            width: 200px;
            height: 130px;
            margin-right: 10px;
            overflow: hidden;
        }

    </style>
</head>
<body>
    <div id="scroll" class="scroll">
        <ul id="munit">
            <li><img src="../BOM/shuzi/3.png" alt=""></li>
            <li><img src="../BOM/shuzi/4.png" alt=""></li>
            <li><img src="../BOM/shuzi/5.png" alt=""></li>
            <li><img src="../BOM/shuzi/6.png" alt=""></li>
            <li><img src="../BOM/shuzi/7.png" alt=""></li>
            <li><img src="../BOM/shuzi/8.png" alt=""></li>
            <li><img src="../BOM/shuzi/9.png" alt=""></li>

            <li><img src="../BOM/shuzi/3.png" alt=""></li>
            <li><img src="../BOM/shuzi/4.png" alt=""></li>
            <li><img src="../BOM/shuzi/5.png" alt=""></li>
            <li><img src="../BOM/shuzi/6.png" alt=""></li>
            <li><img src="../BOM/shuzi/7.png" alt=""></li>
            <li><img src="../BOM/shuzi/8.png" alt=""></li>
            <li><img src="../BOM/shuzi/9.png" alt=""></li>
        </ul>
    </div>

    <script>
        //获取元素
        var scroll = document.getElementById("scroll");
        var munit = document.getElementById("munit");
        var li = munit.children;
        // 进行滚动
        var nowLeft = 0;
        //要找到ul元素运动的折返点
        var back = -1470;//图和边框是li的宽度,展示的有4张图,所以折返点就是1260
        //定时器
        var timer = setInterval(run,20);

        // 鼠标移上scroll停止
        scroll.onmouseover = function(){
            clearInterval(timer);
        }
        // 移开轮播
        scroll.onmouseout = function(){
            timer = setInterval(run,20);
        }

        //运动函数
        function run(){
            nowLeft -= 2;
            //判断是否走到了折返点,走到了,则瞬间切换到0位置
            if(nowLeft <= back){
                nowLeft = 0;
            }
            munit.style.left = nowLeft + "px";
        }

       
    </script>
</body>
</html>

在<div id="scroll">结构给ul新增的一个父级div,这样之后添加图片,后期通过获取ul宽度就可以了计算折算点
1、折返点计算需要通过js自动计算
var back = -munit.offsetWidth;//元素左移,值为负数
2、自动生成另一组对应的图片结构 li
munit.innerHTML = munit.innerHTML + munit.innerHTML;//这样就会增加一组li标签,后期增加图片也会随之增加

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修改部分代码

 

css改写部分:
  /*给ul新增的一个父级div,这样添加图片后期获取ul宽度 就可以了 */
        .scroll .inner{
            position: relative;
            width: 5000px;
        }
        .scroll ul{
            position: absolute;
            height: 130px;
            top: 0;
            left: 0;
            list-style: none;


body改写部分:      
<body>
    <div id="scroll" class="scroll">
       <div class="inner">
           <ul id="munit">
              <li><img src="../BOM/shuzi/3.png" alt=""></li>
              <li><img src="../BOM/shuzi/4.png" alt=""></li>
              <li><img src="../BOM/shuzi/5.png" alt=""></li>
              <li><img src="../BOM/shuzi/6.png" alt=""></li>
              <li><img src="../BOM/shuzi/7.png" alt=""></li>
              <li><img src="../BOM/shuzi/8.png" alt=""></li>
              <li><img src="../BOM/shuzi/9.png" alt=""></li>
              <li><img src="../BOM/shuzi/10.png" alt=""></li>
          </ul>
       </div>
    </div>

js改写部分:
<script>
        //获取元素
        var scroll = document.getElementById("scroll");
        var munit = document.getElementById("munit");

        //改写部分
        //1 折返点计算需要通过Js自动计算
        var back = -munit.offsetWidth;//元素左移,值为负数
        //2 自动生成另一组对应的图片结构 li
        munit.innerHTML = munit.innerHTML + munit.innerHTML;
        // 进行滚动


        var nowLeft = 0;
        //定时器
        var timer = setInterval(run,20);

        // 鼠标移上scroll停止
        scroll.onmouseover = function(){
            clearInterval(timer);
        }
        // 移开轮播
        scroll.onmouseout = function(){
            timer = setInterval(run,20);
        }

        //运动函数
        function run(){
            nowLeft -= 1;
            //判断是否走到了折返点,走到了,则瞬间切换到0位置
            if(nowLeft <= back){
                nowLeft = 0;
            }
            munit.style.left = nowLeft + "px";
        }

    </script>
</body>
</html>

这样的代码耦合性低,也适合任意个数的li、任意大小的图片的加入

posted @ 2021-07-14 18:09  笑人  阅读(310)  评论(0编辑  收藏  举报