Java教程

【JS】使用JavaScript实现轮播图

本文主要是介绍【JS】使用JavaScript实现轮播图,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!
<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>轮播图</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        body {
            display: flex;
            justify-content: center;
            align-items: center;
            flex-direction: column;
        }

        ul,
        ol,
        li {
            list-style: none;
        }

        img {
            width: 100%;
            height: 100%;
            display: block;
        }

        header {
            width: 100%;
            height: 50px;
            text-align: center;
        }

        .banner {
            width: 800px;
            height: 500px;
            position: relative;
            margin: 50px 0;
        }

        .banner > ul {
            width: 100%;
            height: 100%;
            position: relative;
        }

        .banner > ul > li {
            width: 100%;
            height: 100%;
            position: absolute;
            left: 0;
            top: 0;
            opacity: 0;
            transition: opacity .5s linear;
        }

        .banner > ul > li.active {
            opacity: 1;
        }

        .banner > ol {
            width: 200px;
            height: 30px;
            position: absolute;
            left: 30px;
            bottom: 30px;
            background-color: rgba(0, 0, 0, .5);
            display: flex;
            justify-content: space-around;
            align-items: center;
            border-radius: 15px;
        }

        .banner > ol > li {
            width: 20px;
            height: 20px;
            background-color: #fff;
            border-radius: 50px;
        }

        .banner > ol > li.active {
            background-color: orange;
        }

        .banner > div {
            width: 40px;
            height: 60px;
            position: absolute;
            top: 50%;
            transform: translateY(-50%);
            background-color: rgba(0, 0, 0, .5);
            display: flex;
            justify-content: center;
            align-items: center;
            font-size: 30px;
            color: #fff;
            text-align: center;
            line-height: 60px;
        }

        .banner > div.left {
            left: 0;
        }

        .banner > div.right {
            right: 0;
        }

    </style>
</head>
<body>
<header><h1>欢欢商城</h1></header>
<div class="banner">
    <!-- 图片区域 -->
    <ul class="imgBox">
        <li class="active"><img
                src="https://img14.360buyimg.com/pop/s1180x940_jfs/t1/31576/24/16120/43491/62c24333E0d61b301/1c278ce900303beb.jpg.webp"
                alt=""></li>
        <li><img
                src="https://img14.360buyimg.com/pop/s1180x940_jfs/t1/217320/3/17745/94780/6270f940Eb607dc65/b7ae05d4a569739c.jpg.webp"
                alt=""></li>
        <li><img
                src="https://imgcps.jd.com/ling4/100008348542/5Lqs6YCJ5aW96LSn/5L2g5YC85b6X5oul5pyJ/p-5bd8253082acdd181d02f9ee/73226ace/cr/s/q.jpg"
                alt=""></li>
        <li><img
                src="https://imgcps.jd.com/ling4/100025520132/5Lqs6YCJ5aW96LSn/5L2g5YC85b6X5oul5pyJ/p-5bd8253082acdd181d02f9ff/aa4524e6/cr/s/q.jpg"
                alt=""></li>
    </ul>
    <!-- 焦点区域 -->
    <ol>
        <li data-i="0" data-name="point" class="active"></li>
        <li data-i="1" data-name="point"></li>
        <li data-i="2" data-name="point"></li>
        <li data-i="3" data-name="point"></li>
    </ol>
    <!-- 左右切换按钮 -->
    <div class="left">&lt;</div>
    <div class="right">&gt;</div>
</div>

<script>
    // 获取到所有承载图片的li和所有承载焦点的li
    var imgs = document.querySelectorAll('ul>li');
    var points = document.querySelectorAll('ol>li');
    var banner = document.querySelector('.banner');
    var left = document.querySelector('.left');
    var right = document.querySelector('.right');
    // 准备一个变量,表示当前是第几张,默认是0,因为默认显示的是索引第0张
    var index = 0;
    // 书写一个切换一张的函数
    // 约定:
    // 参数为true,我们切换下一张
    // 参数为false,我们切换上一张
    // 参数为数字,我们切换到指定索引的那一张
    function changeOne(type) {
        // 1.让当前这一张消失
        imgs[index].className = ''
        points[index].className = ''

        // 2.根据type传递来的参数,来切换index的值
        if (type === true) {
            index++;
        } else if (type === false) {
            index--;
        } else {
            index = type;
        }
        // 判定一下index的边界值
        if (index >= imgs.length) {
            index = 0;
        }
        if (index < 0) {
            index = imgs.length - 1;
        }
        // 3.让改变后的这一张显示出来
        imgs[index].className = 'active';
        points[index].className = 'active';
    }

    // 给 轮播图区域 盒子绑定点击事件
    banner.onclick = function (e) {
        // console.log('点击事件');
        // 判断点击的是左按钮
        if (e.target.className === 'left') {
            console.log('点击的是左按钮');
            // 切换上一张,调用changeOne 方法传递参数为false
            changeOne(false);
        }
        // 判断点击的是右按钮
        if (e.target.className === 'right') {
            console.log('点击的是右按钮');
            // 切换下一张,调用changeOne 方法传递参数为true
            changeOne(true);
        }
        // 判断点击的是焦点盒子
        if (e.target.dataset.name === 'point') {
            console.log('点击的是焦点盒子');
            // 拿到自己身上记录的索引
            var i = e.target.dataset.i - 0;
            // 切换某一种,调用changeOne方法传递参数为要切换的索引
            changeOne(i);
        }
    }
    // 自动切换功能
    timer = setInterval(function () {
        // 切换到下一张
        changeOne(true)
    }, 3000);
    // 显示,隐藏左右按钮
    banner.addEventListener('mouseenter', function () {
        left.style.display = 'block';
        right.style.display = 'block';
        clearInterval(timer);
    })
    banner.addEventListener('mouseleave', function () {
        left.style.display = 'none';
        right.style.display = 'none';
        timer = setInterval(function () {
            // 切换到下一张
            changeOne(true)
        }, 3000);
    })

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

这篇关于【JS】使用JavaScript实现轮播图的文章就介绍到这儿,希望我们推荐的文章对大家有所帮助,也希望大家多多支持为之网!