JS 轮播图 图片切换(定时器)

标题JS 轮播图 图片切换(定时器)

这次的轮播图与上次的图片切换相比,仅仅是加上了定时器,使其可以自动切换。
上次的图片切换的链接:https://blog.csdn.net/qq_38318589/article/details/99050117
此次全部的代码都在下面,有注释,并有效果图如下:


<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>图片切换title>
    <style>
        .picture {
            position: relative;
            width: 500px;
            height: 333px;
            margin: 0 auto;
            border: 2px solid rgb(231, 127, 217);
            overflow: hidden;
        }

        .radius {           /* 圆点所在的p (容器)  */
            width: 100%;
            height: 10px;
            position: absolute;
            bottom: 30px;
            text-align: center;
        }

        .pg {                         
            position: absolute;
            margin: 0;
            width: 100%;
            height: 20px;
            background-color: rgba(0, 0, 0, .4);
            text-align: center;
            font-size: 16px;
            font-weight: 600;
            color: #fff;
        }

        .title {
            position: absolute;
            width: 100%;
            bottom: 0px;
            text-align: center;
            font-size: 16px;
            font-weight: 600;
            color: rgb(21, 223, 72);
        }

        span {
            display: inline-block;
            border: 10px solid #fdfdfd;
            border-radius: 50%;
        }

        .active {
            border: 10px solid #656466;
        }

        /* 左右箭头  */
        .arrowhead-left,
        .arrowhead-right {
            position: absolute;
            width: 41px;
            height: 69px;
            font-size: 30px;
            line-height: 70px;
            text-align: center;
            color: #D6D8D4;
            background-color: rgba(0,0,0,.3);
        }

        .arrowhead-left {
            left: 0;
            top: 40%;
        }

        .arrowhead-right {
            right: 0;
            top: 40%;
        }
    style>
head>

<body>
    <div class="picture">
        
        <p class="pg">封面p>
        <img src="./image/d8.jpeg" alt="">

        
        <p class="radius">p>
        
        <p class="title">标题p>

        
        <div class="arrowhead-left" id="al"> < div> 
        <div class="arrowhead-right" id="ar"> > div>
    div>

    <script>
        var address = ["./image/d1.jpeg", "./image/d2.jpeg", "./image/d3.jpeg", "./image/d4.jpeg", "./image/d5.jpeg", "./image/d7.jpeg"];
        //  var imgs = document.getElementsByTagName("img");
        var imgs = document.querySelector("img");
        var len = address.length;               //图片地址的数量为len
        var str = "";
        var pp = document.getElementsByTagName("p");//获取的是p标签的集合
        //  var pp  = document.querySelector("p");    //获取的是一个元素
        var al = document.getElementById("al");
        var ar = document.getElementById("ar");
        var n = 0 ;

        //添加span标签(小圆点),个数为len个
        for (i = 0; i < len; i++) {
            str += ' '
        }
        pp[1].innerHTML = str;
       
        var spans = pp[1].getElementsByTagName('span');  //获取p[1]里所有span标签
        spans[0].className = 'active';                  //给第一个span标签添加样式 active

        for (i = 0; i < len; i++) {
            spans[i].index = i;              //自定义索引值
        
            spans[i].onmouseover = function () {            //鼠标指向圆点时的事件
                for (i = 0; i < len; i++) {
                    spans[i].className = "";               //通过循环,清除所有圆点的类名
                }
                n=this.index ;
                this.className = 'active';                 //给鼠标移入的圆点添加类名
                imgs.src = address[this.index];
                pp[0].innerHTML = [this.index + 1] + "/6";    
                pp[2].innerHTML = "风光" + [this.index + 1];
                
            }
           
        }
            
        ar.onclick = function () {            //右侧箭头,点击一次图片向右换一张
            n++;
           if (n>5) {
              n=0;  
           } 
           for (i = 0; i < len; i++) {
                spans[i].className = "";
            }

            spans[n].className = "active";
            imgs.src = address[n];
            pp[0].innerHTML = (n+1) + "/6";
            pp[2].innerHTML = "风光" +(n+1);
          
        }

        al.onclick = function () {        // //左侧箭头,点击一次图片向左换一张
          n--;
         if (n<0) {
             n=(len-1);
         }
         for (i = 0; i < len; i++) {
              spans[i].className = "";
          }         
          spans[n].className = "active";
          imgs.src = address[n];
          pp[0].innerHTML = (n+1) + "/6";
          pp[2].innerHTML = "风光" +(n+1);
        } 
       
       setInterval(ar.onclick,3000);             //添加定时器  setInterval(函数,间隔时间单位为毫秒)
                                                 //此次添加的函数为点击右侧箭头,间隔为3秒
    script>
body>

html>

与上次相比,仅仅添加了一句 setInterval(ar.onclick,3000);
setInterval(函数,间隔时间单位为毫秒)
ar.onclick是点击右侧箭头的函数,3000是3000毫秒,既3秒。

(请忽略图片上的水印,随便找的一个做动图的软件,带水印-_-!)JS 轮播图 图片切换(定时器)_第1张图片

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