最简单的原生js轮播图（适合新手）

怼烎@ 2022-05-23 01:48 161阅读 0赞

<!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>Document</title>
    <script src="jquery.js"></script>
    <style>
    *{
        margin: 0px;
        padding:0px;
        list-style: none;
        text-decoration: none;
    }
    #flash{ /*根据图片的大小来设置外层div的大小*/
        width: 520px;
        height: 280px;
        margin: 0 auto;
        position: relative; /*设置div定位，方便之后图片及圆点位置的设定*/
        border:1px solid black;
    }
    #flash img{
        width: 100%;
        height: 100%;
        position: absolute; /*设置所有图片重叠*/
        left: 0px;
        top: 0px;
        display: none; /*设置所有图片隐藏，通过改变第一个图片的行间样式来使第一个图片显示*/
    }
    #flash ul{
        width: 150px;
        height: 25px;
        border-radius: 20px;
        background-color:rgba(255,255,255,0.5);
        position: absolute;
        left: 35%;
        bottom: 10%;
    }
    #flash ul li{
        width: 12px;
        height: 12px;
        margin-top:5px;
        background-color: #fff;
        border-radius: 50%;
        margin-left: 15px;
        float: left;
    }
    #flash ul .li_1{
        background-color: #f40; /*设置第一个圆点背景色为红色*/
    }
    #flash .span-r{
        width: 50px;
        height: 50px;
        border-radius: 50%;
        position: absolute;
        right: 2%;
        top: 45%;
        background-color: rgba(255,255,255,0.5);
    }
    #flash .span-r span{
        width: 100%;
        height:100%;
        color:rgba(0,0,0,0.5);
        font-size: xx-large;
        font-weight: 700;
        line-height: 50px;
        margin-left: 15px;
        cursor: pointer;
    }
    #flash .span-l{
        width: 50px;
        height: 50px;
        border-radius: 50%;
        position: absolute;
        left: 2%;
        top: 45%;
        background-color: rgba(255,255,255,0.5);
    }
    #flash .span-l span{
        width: 100%;
        height:100%;
        color:rgba(0,0,0,0.5);
        font-size: xx-large;
        font-weight: 700;
        line-height: 50px;
        margin-left: 15px;
        cursor: pointer;
    }
    </style>
    </head>
    <div id="flash">
    <img src="img1.jpg" alt="" style="display: block">
    <img src="img2.jpg" alt="">
    <img src="img3.jpg" alt="">
    <img src="img4.jpg" alt="">
    <img src="img5.jpg" alt="">
    <ul>
    <li class="li_1"></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    </ul>
    <div class="span-r">
    <span>></span>
    </div>
    <div class="span-l">
    <span><</span>
    </div>
    </div>
    <body>
    <script>
        var div = document.getElementById('flash');
        var img = div.getElementsByTagName('img'); /*选中div下所有的图片*/
        var ul = document.getElementsByTagName('ul')[0];
        var li = ul.getElementsByTagName('li');
        var div_r = document.getElementsByTagName('div')[1];
        // var span_r = div_r.getElementsByTagName('span');
        var div_l = document.getElementsByTagName('div')[2];
        // var sapn_l = div_l.getElementsByTagName('span');
        var len = img.length;
        var count = 0; /*设置count来显示当前图片的序号*/
    function run(){ /*将定时器里的函数提取到外部*/
        count++;
        count = count==5?0:count; /*当图片加载到最后一张时，使其归零*/
        for(var i=0;i<len;i++){    
            img[i].style.display = 'none'; /*利用for循环使除当前count位其他图片隐藏*/
        }
        img[count].style.display = 'block'; /*显示当前count的值所代表的图片*/
        for(var i=0;i<li.length;i++){
            li[i].style.backgroundColor = "#fff"; /*原理同上*/
        }
        li[count].style.backgroundColor = "#f40";
    }
        var timer = setInterval(run,1000); /*定义定时器，使图片每隔1s更换一次*/
        div.onmouseover = function(){
        clearInterval(timer);
    }
        div.onmouseleave = function(){ /*定义鼠标移出事件，当鼠标移出div区域，轮播继续*/
        timer = setInterval(run,1000);
    }
        for(var i=0;i<len;i++){
            li[i].index = i; /*定义index记录当前鼠标在li的位置*/
            li[i].onmouseenter = function(){ /*定义鼠标经过事件*/
            for(var i=0;i<len;i++){ /*通过for循环将所有图片隐藏，圆点背景设为白色*/
                li[i].style.background = '#fff';
                img[i].style.display = 'none';
            }
        this.style.background = '#f40'; /*设置当前所指圆点的背景色*/
        img[this.index].style.display = 'block'; /*使圆点对应的图片显示*/
        }
    }
        div_r.onclick = function(){ /*因为span没有设置宽高，直接把事件添加到他的父级*/
        run(); /*直接调用现成的run函数*/
    }
    function reverse(){
        count--;
        count = count==-1?4:count;
        for(var i=0;i<len;i++){
            img[i].style.display = 'none'; /*利用for循环使除当前count位其他图片隐藏*/
        }
        img[count].style.display = 'block'; /*显示当前count的值所代表的图片*/
        for(var i=0;i<li.length;i++){
            li[i].style.backgroundColor = "#fff"; /*原理同上*/
        }
        li[count].style.backgroundColor = "#f40";
    }
        div_l.onclick = function(){
        reverse(); /*重新设置函数*/
    }
    </script>
    </body>
    </html>

运行效果如下：

![70][]

[70]: /images/20220523/8df01075bcfd4be2a5a3885d320bb57f.png