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;