轮播图案例![Snipaste_2022-01-23_20-33-27.jpg](https://p6-juejin.b

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

<head>
  <meta charset="UTF-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>QQ音乐轮播图</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    li {
      list-style: none;
    }

    .main {
      width: 700px;
      margin: auto;
      background: #000;
    }

    .slides {
      height: 320px;
      position: relative;
    }

    .slides ul li {
      /* display: none; */
      position: absolute;
      top: 0;
      left: 0;
      opacity: 0;
      /* 这里实现淡入淡出的关键 */
      transition: all 0.3s;
    }

    .slides li.active {
      /* display: block; */
      opacity: 1;
    }

    .slides .extra {
      width: 700px;
      height: 53px;
      line-height: 53px;
      position: absolute;
      bottom: 0px;
      background-color: rgba(0, 0, 0, 0.8);
      z-index: 10;
    }

    .slides .extra h3 {
      width: 82%;
      margin: 0;
      margin-right: 20px;
      padding-left: 20px;
      color: #98e404;
      font-size: 28px;
      float: left;
      font-weight: 500;
      font-family: 'Microsoft Yahei', Tahoma, Geneva;
    }

    .slides .extra a {
      width: 30px;
      height: 29px;
      display: block;
      float: left;
      margin-top: 12px;
      margin-right: 3px;
      background-image: url(./assets/icon_focus_switch.png);
    }

    .slides .extra .prev {
      background-position: 0 0;
    }

    .slides .extra .prev:hover {
      background-position: -30px 0;
    }

    .slides .extra .next {
      background-position: -60px 0;
    }

    .slides .extra .next:hover {
      background-position: -90px 0;
    }

    .indicator {
      padding: 10px 0;
    }

    .indicator ul {
      list-style-type: none;
      margin: 0 0 0 4px;
      padding: 0;
      overflow: hidden;
    }

    .indicator ul li {
      position: relative;
      float: left;
      width: 60px;
      margin: 0 4px 0 5px;
      text-align: center;

      cursor: pointer;
    }

    .indicator li img {
      display: block;
      border: 0;
      text-align: center;
      width: 60px;
    }

    .indicator li .mask {
      width: 60px;
      height: 60px;
      position: absolute;
      top: 0;
      left: 0;
      background-color: rgba(0, 0, 0, 0.4);
    }

    .indicator li .border {
      display: none;
      width: 54px;
      position: absolute;
      bottom: 0;
      left: 0;
      z-index: 20;
      border: 3px solid #98e404;
    }

    /* li里面的mask 和 border 刚开始都是显示的 */
    /* 我们写一个样式css */
    .indicator .active .mask {
      display: none;
    }

    .indicator .active .border {
      display: block;
    }
  </style>
</head>

<body>


  <div class="main">
    <div class="slides">
      <ul>
        <li class="active">
          <a href="#"><img src="./assets/b_01.jpg" alt="第1张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_02.jpg" alt="第2张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_03.jpg" alt="第3张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_04.jpg" alt="第4张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_05.jpg" alt="第5张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_06.jpg" alt="第6张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_07.jpg" alt="第7张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_08.jpg" alt="第8张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_09.jpg" alt="第9张图的描述信息" /></a>
        </li>
        <li>
          <a href="#"><img src="./assets/b_10.jpg" alt="第9张图的描述信息" /></a>
        </li>
      </ul>

      <div class="extra">
        <h3>第1张图的描述信息</h3>
        <a class="prev" href="javascript:;"></a>
        <a class="next" href="javascript:;"></a>
      </div>
    </div>
    <div class="indicator">
      <ul>
        <li class="active">
          <img src="assets/s_01.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_02.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_03.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_04.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_05.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_06.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_07.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_08.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_09.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
        <li>
          <img src="assets/s_10.jpg" />
          <span class="mask"></span>
          <span class="border"></span>
        </li>
      </ul>
    </div>
  </div>
  <script>
    // 添加load
    window.addEventListener('load', function () {
      // 获取元素
      let slides = document.querySelectorAll('.slides li')
      let extra = document.querySelector('.extra>h3')
      let indicator = document.querySelectorAll('.indicator  li')
      let next = document.querySelector('.next')
      let prev = document.querySelector('.prev')
      let main = document.querySelector('.main')
      let num = 0
      // console.log(slides, extra, indicator);
      // 遍历绑定事件
      indicator.forEach(function (v, i) {
        v.addEventListener('click', function () {
          // console.log(1);
          // 移除当前样式
          document.querySelector('.indicator .active').classList.remove('active')
          // 为当前元素添加样式
          v.classList.add('active')
          // 修改文本描述
          extra.innerHTML = `第${i + 1}张图的描述信息`
          //切换大图
          document.querySelector('.slides .active').classList.remove('active')
          slides[i].classList.add('active')
          // 重置索引
          num = i
        })
      })
      // 下一张
      next.addEventListener('click', function () {
        num++
        // 判断索引是否越界
        if (num > indicator.length - 1) {
          num = 0
        }
        // 调用索引位置的li元素的click单击事件
        indicator[num].click()
      })
      // 上一张
      prev.addEventListener('click', function () {
        num--
        // 判断索引是否越界
        if (num < 0) {
          num = indicator.length - 1
        }
        // 调用索引位置的li元素的click单击事件
        indicator[num].click()
      })
      // 修改细节，如果先单击某个缩略图，再单击上一张和下一张，索引位置出现异常，我们单击缩略图并没有更新当前正确的索引位置，索引还是从0开始

      // 自动轮播
      let timeId = setInterval(function () {
        next.click()
      }, 1000)
      // 鼠标移入，轮播停止，鼠标移出，轮播继续
      main.addEventListener('mouseenter', function () {
        clearInterval(timeId)
      })
      main.addEventListener('mouseleave', function () {
        timeId = setInterval(function () {
          next.click()
        }, 1000)
      })
    })
  </script>
</body>

</html>