js写轮播图，逐步完善

1、自动轮播

2、点击更换

3、自动播放加左右箭头点击切换

4、完整版轮播图

1、自动轮播

用定时器setInterval()来写，可以实现自动播放

<!DOCTYPE html>
<html lang="en">

<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>轮播图点击切换</title>
    <style>
        * {
            box-sizing: border-box;
        }

        .slider {
            width: 560px;
            height: 400px;
            overflow: hidden;
        }

        .slider-wrapper {
            width: 100%;
            height: 320px;
        }

        .slider-wrapper img {
            width: 100%;
            height: 100%;
            display: block;
        }

        .slider-footer {
            height: 80px;
            background-color: rgb(100, 67, 68);
            padding: 12px 12px 0 12px;
            position: relative;
        }

        .slider-footer .toggle {
            position: absolute;
            right: 0;
            top: 12px;
            display: flex;
        }

        .slider-footer .toggle button {
            margin-right: 12px;
            width: 28px;
            height: 28px;
            appearance: none;
            border: none;
            background: rgba(255, 255, 255, 0.1);
            color: #fff;
            border-radius: 4px;
            cursor: pointer;
        }

        .slider-footer .toggle button:hover {
            background: rgba(255, 255, 255, 0.2);
        }

        .slider-footer p {
            margin: 0;
            color: #fff;
            font-size: 18px;
            margin-bottom: 10px;
        }

        .slider-indicator {
            margin: 0;
            padding: 0;
            list-style: none;
            display: flex;
            align-items: center;
        }

        .slider-indicator li {
            width: 8px;
            height: 8px;
            margin: 4px;
            border-radius: 50%;
            background: #fff;
            opacity: 0.4;
            cursor: pointer;
        }

        .slider-indicator li.active {
            width: 12px;
            height: 12px;
            opacity: 1;
        }
    </style>
</head>

<body>
    <div class="slider">
        <div class="slider-wrapper">
            <img src="./images/slider01.jpg" alt="" />
        </div>
        <div class="slider-footer">
            <p>对人类来说会不会太超前了？</p>
            <ul class="slider-indicator">
                <li class="active"></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
            </ul>
            <div class="toggle">
                <button class="prev">&lt;</button>
                <button class="next">&gt;</button>
            </div>
        </div>
    </div>
    <script>
        // 1. 初始数据
        const sliderData = [
            { url: './images/slider01.jpg', title: '对人类来说会不会太超前了？', color: 'rgb(100, 67, 68)' },
            { url: './images/slider02.jpg', title: '开启剑与雪的黑暗传说！', color: 'rgb(43, 35, 26)' },
            { url: './images/slider03.jpg', title: '真正的jo厨出现了！', color: 'rgb(36, 31, 33)' },
            { url: './images/slider04.jpg', title: '李玉刚：让世界通过B站看到东方大国文化', color: 'rgb(139, 98, 66)' },
            { url: './images/slider05.jpg', title: '快来分享你的寒假日常吧~', color: 'rgb(67, 90, 92)' },
            { url: './images/slider06.jpg', title: '哔哩哔哩小年YEAH', color: 'rgb(166, 131, 143)' },
            { url: './images/slider07.jpg', title: '一站式解决你的电脑配置问题！！！', color: 'rgb(53, 29, 25)' },
            { url: './images/slider08.jpg', title: '谁不想和小猫咪贴贴呢！', color: 'rgb(99, 72, 114)' },
        ]

        //获取元素
        const img = document.querySelector('.slider-wrapper img')
        const p = document.querySelector(".slider-footer p")
        const footer = document.querySelector('.slider-footer')
        const slider = document.querySelector(".slider")
        const lis = document.querySelectorAll('.slider-indicator li')
        const next = document.querySelector('.toggle .next')
        const prev = document.querySelector('.toggle .prev')

        let i = 0

        //开启定时器
        let timer = setInterval(function () {

            i++
            if (i === sliderData.length) {
                i = 0
            }
            // 设置图片
            img.src = sliderData[i].url
            // 设置标题
            p.innerHTML = sliderData[i].title

            // 设置底部区域背景色
            footer.style.backgroundColor = sliderData[i].color
            // 设置小圆圈样式
            // 把其他某个li的active移除 再给对应的li设置
            document.querySelector('.slider-indicator .active').classList.remove('active')

            lis[i].classList.add('active')

        }, 1000)
    </script>
</body>

</html>

2、点击更换

点击那个小圆点就跳到对应位置

<!DOCTYPE html>
<html lang="en">

<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>轮播图点击切换</title>
  <style>
    * {
      box-sizing: border-box;
    }

    .slider {
      width: 560px;
      height: 400px;
      overflow: hidden;
    }

    .slider-wrapper {
      width: 100%;
      height: 320px;
    }

    .slider-wrapper img {
      width: 100%;
      height: 100%;
      display: block;
    }

    .slider-footer {
      height: 80px;
      background-color: rgb(100, 67, 68);
      padding: 12px 12px 0 12px;
      position: relative;
    }

    .slider-footer .toggle {
      position: absolute;
      right: 0;
      top: 12px;
      display: flex;
    }

    .slider-footer .toggle button {
      margin-right: 12px;
      width: 28px;
      height: 28px;
      appearance: none;
      border: none;
      background: rgba(255, 255, 255, 0.1);
      color: #fff;
      border-radius: 4px;
      cursor: pointer;
    }

    .slider-footer .toggle button:hover {
      background: rgba(255, 255, 255, 0.2);
    }

    .slider-footer p {
      margin: 0;
      color: #fff;
      font-size: 18px;
      margin-bottom: 10px;
    }

    .slider-indicator {
      margin: 0;
      padding: 0;
      list-style: none;
      display: flex;
      align-items: center;
    }

    .slider-indicator li {
      width: 8px;
      height: 8px;
      margin: 4px;
      border-radius: 50%;
      background: #fff;
      opacity: 0.4;
      cursor: pointer;
    }

    .slider-indicator li.active {
      width: 12px;
      height: 12px;
      opacity: 1;
    }
  </style>
</head>

<body>
  <div class="slider">
    <div class="slider-wrapper">
      <img src="./images/slider01.jpg" alt="" />
    </div>
    <div class="slider-footer">
      <p>对人类来说会不会太超前了？</p>
      <ul class="slider-indicator">
        <li class="active"></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
      </ul>
      <div class="toggle">
        <button class="prev">&lt;</button>
        <button class="next">&gt;</button>
      </div>
    </div>
  </div>
  <script>
    // 1. 初始数据
    const sliderData = [
      { url: './images/slider01.jpg', title: '对人类来说会不会太超前了？', color: 'rgb(100, 67, 68)' },
      { url: './images/slider02.jpg', title: '开启剑与雪的黑暗传说！', color: 'rgb(43, 35, 26)' },
      { url: './images/slider03.jpg', title: '真正的jo厨出现了！', color: 'rgb(36, 31, 33)' },
      { url: './images/slider04.jpg', title: '李玉刚：让世界通过B站看到东方大国文化', color: 'rgb(139, 98, 66)' },
      { url: './images/slider05.jpg', title: '快来分享你的寒假日常吧~', color: 'rgb(67, 90, 92)' },
      { url: './images/slider06.jpg', title: '哔哩哔哩小年YEAH', color: 'rgb(166, 131, 143)' },
      { url: './images/slider07.jpg', title: '一站式解决你的电脑配置问题！！！', color: 'rgb(53, 29, 25)' },
      { url: './images/slider08.jpg', title: '谁不想和小猫咪贴贴呢！', color: 'rgb(99, 72, 114)' },
    ]
    //获取元素
    const img = document.querySelector('.slider-wrapper img')
        const p = document.querySelector(".slider-footer p")
        const footer = document.querySelector('.slider-footer')
        const slider = document.querySelector(".slider")
        const lis = document.querySelectorAll('.slider-indicator li')
        const next = document.querySelector('.toggle .next')
        const prev = document.querySelector('.toggle .prev')

//遍历所有的li，给每个li绑定一个点击事件
        for(let i=0;i<lis.length;i++){
            lis[i].addEventListener('click',function() {
              //移出所有的active类
              document.querySelector('.slider-indicator .active').classList.remove('active')
            //谁点击谁添加active类
              this.classList.add('active')
              img.src = sliderData[i].url
            p.innerHTML = sliderData[i].title
            footer.style.backgroundColor = sliderData[i].color
            })
        }

  </script>
</body>

</html>

3、自动播放加左右箭头点击切换

需求：要自动播放

点击左右按钮可以跳转

鼠标移入停止自动播放，鼠标离开继续自动播放

思路：

需要开启定时器来实现自动播放

给左右按钮添加点击事件

给整体添加鼠标移入清除定时器功能

鼠标移出添加开启定时器功能

<!DOCTYPE html>
<html lang="en">

<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>轮播图点击切换</title>
    <style>
        * {
            box-sizing: border-box;
        }

        .slider {
            width: 560px;
            height: 400px;
            overflow: hidden;
        }

        .slider-wrapper {
            width: 100%;
            height: 320px;
        }

        .slider-wrapper img {
            width: 100%;
            height: 100%;
            display: block;
        }

        .slider-footer {
            height: 80px;
            background-color: rgb(100, 67, 68);
            padding: 12px 12px 0 12px;
            position: relative;
        }

        .slider-footer .toggle {
            position: absolute;
            right: 0;
            top: 12px;
            display: flex;
        }

        .slider-footer .toggle button {
            margin-right: 12px;
            width: 28px;
            height: 28px;
            appearance: none;
            border: none;
            background: rgba(255, 255, 255, 0.1);
            color: #fff;
            border-radius: 4px;
            cursor: pointer;
        }

        .slider-footer .toggle button:hover {
            background: rgba(255, 255, 255, 0.2);
        }

        .slider-footer p {
            margin: 0;
            color: #fff;
            font-size: 18px;
            margin-bottom: 10px;
        }

        .slider-indicator {
            margin: 0;
            padding: 0;
            list-style: none;
            display: flex;
            align-items: center;
        }

        .slider-indicator li {
            width: 8px;
            height: 8px;
            margin: 4px;
            border-radius: 50%;
            background: #fff;
            opacity: 0.4;
            cursor: pointer;
        }

        .slider-indicator li.active {
            width: 12px;
            height: 12px;
            opacity: 1;
        }
    </style>
</head>

<body>
    <div class="slider">
        <div class="slider-wrapper">
            <img src="./images/slider01.jpg" alt="" />
        </div>
        <div class="slider-footer">
            <p>对人类来说会不会太超前了？</p>
            <ul class="slider-indicator">
                <li class="active"></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
            </ul>
            <div class="toggle">
                <button class="prev">&lt;</button>
                <button class="next">&gt;</button>
            </div>
        </div>
    </div>
    <script>
        // 1. 初始数据
        const sliderData = [
            { url: './images/slider01.jpg', title: '对人类来说会不会太超前了？', color: 'rgb(100, 67, 68)' },
            { url: './images/slider02.jpg', title: '开启剑与雪的黑暗传说！', color: 'rgb(43, 35, 26)' },
            { url: './images/slider03.jpg', title: '真正的jo厨出现了！', color: 'rgb(36, 31, 33)' },
            { url: './images/slider04.jpg', title: '李玉刚：让世界通过B站看到东方大国文化', color: 'rgb(139, 98, 66)' },
            { url: './images/slider05.jpg', title: '快来分享你的寒假日常吧~', color: 'rgb(67, 90, 92)' },
            { url: './images/slider06.jpg', title: '哔哩哔哩小年YEAH', color: 'rgb(166, 131, 143)' },
            { url: './images/slider07.jpg', title: '一站式解决你的电脑配置问题！！！', color: 'rgb(53, 29, 25)' },
            { url: './images/slider08.jpg', title: '谁不想和小猫咪贴贴呢！', color: 'rgb(99, 72, 114)' },
        ]
        const img = document.querySelector('.slider-wrapper img')
        const p = document.querySelector(".slider-footer p")
        const footer = document.querySelector('.slider-footer')
        const slider = document.querySelector(".slider")
        const lis = document.querySelectorAll('.slider-indicator li')
        const next = document.querySelector('.toggle .next')
        const prev = document.querySelector('.toggle .prev')

        let i = 0

        //开启定时器
        let timer = setInterval(function () {

            i++
            if (i === sliderData.length) {
                i = 0
            }
            img.src = sliderData[i].url
            p.innerHTML = sliderData[i].title
            footer.style.backgroundColor = sliderData[i].color

            document.querySelector('.slider-indicator .active').classList.remove('active')

            lis[i].classList.add('active')

        }, 1000)

        next.addEventListener('click', function () {
            i++
            if (i === sliderData.length) {
                i = 0
            }
            img.src = sliderData[i].url
            p.innerHTML = sliderData[i].title
            footer.style.backgroundColor = sliderData[i].color

            document.querySelector('.slider-indicator .active').classList.remove('active')

            lis[i].classList.add('active')


        })
        prev.addEventListener('click',function() {
            i--
            if (i< 0) {
                i = sliderData.length
            }
            img.src = sliderData[i].url
            p.innerHTML = sliderData[i].title
            footer.style.backgroundColor = sliderData[i].color

            document.querySelector('.slider-indicator .active').classList.remove('active')

            lis[i].classList.add('active')

        })

        slider.addEventListener('mouseenter', function () {
            clearInterval(timer)
        })
        slider.addEventListener('mouseleave', function () {
            timer = setInterval(function () {

                i++
                if (i === sliderData.length) {
                    i = 0
                }
                img.src = sliderData[i].url
                p.innerHTML = sliderData[i].title
                footer.style.backgroundColor = sliderData[i].color

                document.querySelector('.slider-indicator .active').classList.remove('active')

                lis[i].classList.add('active')

            }, 1000)

        })


    </script>
</body>

</html>

优化代码：把重复的代码封装成一个为toggle() 的函数，哪里需要，哪里调用，减少代码冗余

<!DOCTYPE html>
<html lang="en">
  <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>轮播图点击切换</title>
    <style>
      * {
        box-sizing: border-box;
      }

      .slider {
        width: 560px;
        height: 400px;
        overflow: hidden;
      }

      .slider-wrapper {
        width: 100%;
        height: 320px;
      }

      .slider-wrapper img {
        width: 100%;
        height: 100%;
        display: block;
      }

      .slider-footer {
        height: 80px;
        background-color: rgb(100, 67, 68);
        padding: 12px 12px 0 12px;
        position: relative;
      }

      .slider-footer .toggle {
        position: absolute;
        right: 0;
        top: 12px;
        display: flex;
      }

      .slider-footer .toggle button {
        margin-right: 12px;
        width: 28px;
        height: 28px;
        appearance: none;
        border: none;
        background: rgba(255, 255, 255, 0.1);
        color: #fff;
        border-radius: 4px;
        cursor: pointer;
      }

      .slider-footer .toggle button:hover {
        background: rgba(255, 255, 255, 0.2);
      }

      .slider-footer p {
        margin: 0;
        color: #fff;
        font-size: 18px;
        margin-bottom: 10px;
      }

      .slider-indicator {
        margin: 0;
        padding: 0;
        list-style: none;
        display: flex;
        align-items: center;
      }

      .slider-indicator li {
        width: 8px;
        height: 8px;
        margin: 4px;
        border-radius: 50%;
        background: #fff;
        opacity: 0.4;
        cursor: pointer;
      }

      .slider-indicator li.active {
        width: 12px;
        height: 12px;
        opacity: 1;
      }
    </style>
  </head>

  <body>
    <div class="slider">
      <div class="slider-wrapper">
        <img src="./images/slider01.jpg" alt="" />
      </div>
      <div class="slider-footer">
        <p>对人类来说会不会太超前了？</p>
        <ul class="slider-indicator">
          <li class="active"></li>
          <li></li>
          <li></li>
          <li></li>
          <li></li>
          <li></li>
          <li></li>
          <li></li>
        </ul>
        <div class="toggle">
          <button class="prev">&lt;</button>
          <button class="next">&gt;</button>
        </div>
      </div>
    </div>
    <script>
      // 1. 初始数据
      const sliderData = [
        {
          url: './images/slider01.jpg',
          title: '对人类来说会不会太超前了？',
          color: 'rgb(100, 67, 68)',
        },
        {
          url: './images/slider02.jpg',
          title: '开启剑与雪的黑暗传说！',
          color: 'rgb(43, 35, 26)',
        },
        {
          url: './images/slider03.jpg',
          title: '真正的jo厨出现了！',
          color: 'rgb(36, 31, 33)',
        },
        {
          url: './images/slider04.jpg',
          title: '李玉刚：让世界通过B站看到东方大国文化',
          color: 'rgb(139, 98, 66)',
        },
        {
          url: './images/slider05.jpg',
          title: '快来分享你的寒假日常吧~',
          color: 'rgb(67, 90, 92)',
        },
        {
          url: './images/slider06.jpg',
          title: '哔哩哔哩小年YEAH',
          color: 'rgb(166, 131, 143)',
        },
        {
          url: './images/slider07.jpg',
          title: '一站式解决你的电脑配置问题！！！',
          color: 'rgb(53, 29, 25)',
        },
        {
          url: './images/slider08.jpg',
          title: '谁不想和小猫咪贴贴呢！',
          color: 'rgb(99, 72, 114)',
        },
      ]

      // 找到相关元素
      const oImg = document.querySelector('.slider-wrapper > img')
      const title = document.querySelector('.slider-footer > p')
      const sliderFooter = document.querySelector('.slider-footer')
      const lis = document.querySelectorAll('.slider-indicator li')
      const prev = document.querySelector('.prev')
      const next = document.querySelector('.next')
      const slider = document.querySelector('.slider')

      // 定义一个变量
      let i = 0
      // 开启定时器 开启自动播放
      let timerId = setInterval(function() {
        // i++
        // if (i === sliderData.length) {
        //   i = 0
        // }
        // toggle()

        // 方式二 模拟点击右侧按钮
        next.click()
      }
      , 1500)

      // 给右侧按钮绑定事件
      next.addEventListener('click', function () {
        i++
        if (i === sliderData.length) {
          i = 0
        }
        toggle()
      })

      // 给左侧按钮绑定事件
      prev.addEventListener('click', function () {
        i--
        if (i < 0) {
          i = sliderData.length - 1
        }
        toggle()
      })

      // 给slider绑定鼠标移入事件
      slider.addEventListener('mouseenter', function () {
        clearInterval(timerId)
      })
      // 给slider绑定鼠标移出事件
      slider.addEventListener('mouseleave', function () {
        timerId = setInterval(function () {
         next.click()
        }, 1500)
      })

      // 切换
      function toggle() {
        // 设置图片
        oImg.src = sliderData[i].url
        // 设置标题
        title.innerHTML = sliderData[i].title
        // 设置底部区域背景色
        sliderFooter.style.backgroundColor = sliderData[i].color
        // 设置小圆圈样式
        // 把其他某个li的active移除 再给对应的li设置
        document
          .querySelector('.slider-indicator .active').classList.remove('active')
        // lis[i].classList.add('active') 方式二
        document.querySelector(`.slider-indicator li:nth-child(${i + 1})`).classList.add('active')
      }
    </script>
  </body>
</html>

4、完整版轮播图

结合以上所有功能，是一个综合

<!DOCTYPE html>
<html lang="en">

<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>轮播图点击切换</title>
    <style>
        * {
            box-sizing: border-box;
        }

        .slider {
            width: 560px;
            height: 400px;
            overflow: hidden;
        }

        .slider-wrapper {
            width: 100%;
            height: 320px;
        }

        .slider-wrapper img {
            width: 100%;
            height: 100%;
            display: block;
        }

        .slider-footer {
            height: 80px;
            background-color: rgb(100, 67, 68);
            padding: 12px 12px 0 12px;
            position: relative;
        }

        .slider-footer .toggle {
            position: absolute;
            right: 0;
            top: 12px;
            display: flex;
        }

        .slider-footer .toggle button {
            margin-right: 12px;
            width: 28px;
            height: 28px;
            appearance: none;
            border: none;
            background: rgba(255, 255, 255, 0.1);
            color: #fff;
            border-radius: 4px;
            cursor: pointer;
        }

        .slider-footer .toggle button:hover {
            background: rgba(255, 255, 255, 0.2);
        }

        .slider-footer p {
            margin: 0;
            color: #fff;
            font-size: 18px;
            margin-bottom: 10px;
        }

        .slider-indicator {
            margin: 0;
            padding: 0;
            list-style: none;
            display: flex;
            align-items: center;
        }

        .slider-indicator li {
            width: 8px;
            height: 8px;
            margin: 4px;
            border-radius: 50%;
            background: #fff;
            opacity: 0.4;
            cursor: pointer;
        }

        .slider-indicator li.active {
            width: 12px;
            height: 12px;
            opacity: 1;
        }
    </style>
</head>

<body>
    <div class="slider">
        <div class="slider-wrapper">
            <img src="./images/slider01.jpg" alt="" />
        </div>
        <div class="slider-footer">
            <p>对人类来说会不会太超前了？</p>
            <ul class="slider-indicator">
                <li class="active"></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
                <li></li>
            </ul>
            <div class="toggle">
                <button class="prev">&lt;</button>
                <button class="next">&gt;</button>
            </div>
        </div>
    </div>
    <script>
        // 1. 初始数据
        const sliderData = [
            { url: './images/slider01.jpg', title: '对人类来说会不会太超前了？', color: 'rgb(100, 67, 68)' },
            { url: './images/slider02.jpg', title: '开启剑与雪的黑暗传说！', color: 'rgb(43, 35, 26)' },
            { url: './images/slider03.jpg', title: '真正的jo厨出现了！', color: 'rgb(36, 31, 33)' },
            { url: './images/slider04.jpg', title: '李玉刚：让世界通过B站看到东方大国文化', color: 'rgb(139, 98, 66)' },
            { url: './images/slider05.jpg', title: '快来分享你的寒假日常吧~', color: 'rgb(67, 90, 92)' },
            { url: './images/slider06.jpg', title: '哔哩哔哩小年YEAH', color: 'rgb(166, 131, 143)' },
            { url: './images/slider07.jpg', title: '一站式解决你的电脑配置问题！！！', color: 'rgb(53, 29, 25)' },
            { url: './images/slider08.jpg', title: '谁不想和小猫咪贴贴呢！', color: 'rgb(99, 72, 114)' },
        ]
        const img = document.querySelector('.slider-wrapper img')
        const p = document.querySelector(".slider-footer p")
        const footer = document.querySelector('.slider-footer')
        const slider = document.querySelector(".slider")
        const lis = document.querySelectorAll('.slider-indicator li')
        const next = document.querySelector('.toggle .next')
        const prev = document.querySelector('.toggle .prev')

        let i = 0


        //开启定时器
        let timer = setInterval(function () {


            next.click()

        }, 1000)

        //右侧点击
        next.addEventListener('click', function () {
            i++
            if (i === sliderData.length) {
                i = 0
            }

            toggle()


        })
        //左侧点击
        prev.addEventListener('click', function () {
            i--
            if (i < 0) {
                i = sliderData.length
            }


            toggle()


        })

        //鼠标移入清除定时器
        slider.addEventListener('mouseenter', function () {
            clearInterval(timer)
        })
        //鼠标移出，开启定时器
        slider.addEventListener('mouseleave', function () {
            timer = setInterval(function () {

                next.click()

            }, 1000)

        })
        //给每个li(小圆点)设置点击事件
        for (let j = 0; j < lis.length; j++) {
            lis[j].addEventListener('click', function () {
                document.querySelector('.slider-indicator .active').classList.remove('active')
                this.classList.add('active')
                img.src = sliderData[j].url
                p.innerHTML = sliderData[j].title
                footer.style.backgroundColor = sliderData[j].color
                i = j
            })
        }
        //相同代码封装成一个函数，方便复用
        function toggle() {
            img.src = sliderData[i].url
            p.innerHTML = sliderData[i].title
            footer.style.backgroundColor = sliderData[i].color

            document.querySelector('.slider-indicator .active').classList.remove('active')

            lis[i].classList.add('active')

        }


    </script>
</body>

</html>