如何实现轮播图 Slideshow

本教程将学习如何使用CSS和JavaScript创建一个轮播图组件。

轮播图

轮播图，在英语中称为Slideshow，或是Carousel，用于循环展示图片，文字，或是视频。

我们先看一个例子：

轮播图有什么功能？

通过上面的例子，我们想一想，一个轮播图包含什么功能呢？

由有几张图片组成
头部有当前是第几张的序号，底部有当前图片位置的小按钮
左右两边是上一张下一张的按钮

创建一个轮播图

步骤1，创建HTML

增加图片，序号，切换按钮的HTML

<!-- 创建一个容器包含图片内容 -->
<div class="slideshow-container">
  <!-- 第一张图片 -->
  <div class="mySlides fade">
    <div class="numbertext">1 / 3</div>
    <img src="img1.jpg" style="width:100%">
    <div class="text">标题1</div>
  </div>

  <div class="mySlides fade">
    <div class="numbertext">2 / 3</div>
    <img src="img2.jpg" style="width:100%">
    <div class="text">标题2</div>
  </div>

  <div class="mySlides fade">
    <div class="numbertext">3 / 3</div>
    <img src="img3.jpg" style="width:100%">
    <div class="text">标题3</div>
  </div>

  <!-- 上一张/下一张的按钮  -->
  <a class="prev" onclick="plusSlides(-1)">❮</a>
  <a class="next" onclick="plusSlides(1)">❯</a>
</div>
<br>

<!-- 底部的指示按钮 -->
<div style="text-align:center">
  <span class="dot" onclick="currentSlide(1)"></span>
  <span class="dot" onclick="currentSlide(2)"></span>
  <span class="dot" onclick="currentSlide(3)"></span>
</div>

步骤2 添加CSS：

为上一张，下一张的按钮，还有标题，指示按钮增加样式：

* {box-sizing:border-box}

/* 轮播图容器 */
.slideshow-container {
  max-width: 1000px;
  position: relative;
  margin: auto;
}

.mySlides {
    display: none;
}

/* 上一张和下一张的按钮 */
.prev, .next {
  cursor: pointer;
  position: absolute;
  top: 50%;
  width: auto;
  margin-top: -22px;
  padding: 16px;
  color: white;
  font-weight: bold;
  font-size: 18px;
  transition: 0.6s ease;
  border-radius: 0 3px 3px 0;
}

/* 将”下一张“的按钮定位在右边 */
.next {
  right: 0;
  border-radius: 3px 0 0 3px;
}

/* 鼠标移到按钮上，增加一个有点透明的黑色背景 */
.prev:hover, .next:hover {
  background-color: rgba(0,0,0,0.8);
}

/* 标题的文本 */
.text {
  color: #f2f2f2;
  font-size: 15px;
  padding: 8px 12px;
  position: absolute;
  bottom: 8px;
  width: 100%;
  text-align: center;
}

/* 图片顺序的文本，(如，1/3) */
.numbertext {
  color: #f2f2f2;
  font-size: 12px;
  padding: 8px 12px;
  position: absolute;
  top: 0;
}

/* 底部的指示按钮 */
.dot {
  cursor:pointer;
  height: 13px;
  width: 13px;
  margin: 0 2px;
  background-color: #bbb;
  border-radius: 50%;
  display: inline-block;
  transition: background-color 0.6s ease;
}

.active, .dot:hover {
  background-color: #717171;
}

/* 淡入淡出的动画 */
.fade {
  -webkit-animation-name: fade;
  -webkit-animation-duration: 1.5s;
  animation-name: fade;
  animation-duration: 1.5s;
}

@-webkit-keyframes fade {
  from {opacity: .4} 
  to {opacity: 1}
}

@keyframes fade {
  from {opacity: .4} 
  to {opacity: 1}
}

步骤3：增加JavaScript：

实现点击按钮，会跳转到当前的幻灯片

var slideIndex = 1;
showSlides(slideIndex);
// 展示上一张/下一
function plusSlides(n) {
  showSlides(slideIndex += n);
}
// 展示并记录指定位置的图片
function currentSlide(n) {
  showSlides(slideIndex = n);
}
// 展示指定位置的图片
function showSlides(n) {
  var i;
  var slides = document.getElementsByClassName("mySlides");
  var dots = document.getElementsByClassName("dot");
  if (n > slides.length) {
    slideIndex = 1
  }
  if (n < 1) {
    slideIndex = slides.length
  }
  for (i = 0; i < slides.length; i++) {
    slides[i].style.display = "none";
  }
  for (i = 0; i < dots.length; i++) {
    dots[i].className = dots[i].className.replace(" active", "");
  }
  slides[slideIndex - 1].style.display = "block";
  dots[slideIndex - 1].className += " active";
}

最终轮播图的效果如下

<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <style>
    * {
      box-sizing: border-box
    }

    body {
      font-family: Verdana, sans-serif;
      margin: 0
    }

    .mySlides {
      display: none
    }
    /* 轮播图容器 */

    .slideshow-container {
      max-width: 1000px;
      position: relative;
      margin: auto;
    }
    /* 上一张和下一张的按钮 */

    .prev,
    .next {
      cursor: pointer;
      position: absolute;
      top: 50%;
      width: auto;
      padding: 16px;
      margin-top: -22px;
      color: white;
      font-weight: bold;
      font-size: 18px;
      transition: 0.6s ease;
      border-radius: 0 3px 3px 0;
    }
    /* 将”下一张“的按钮定位在右边 */

    .next {
      right: 0;
      border-radius: 3px 0 0 3px;
    }
    /* 鼠标移到按钮上，增加一个有点透明的黑色背景 */

    .prev:hover,
    .next:hover {
      background-color: rgba(0, 0, 0, 0.8);
    }
    /* 标题的文本 */

    .text {
      color: #f2f2f2;
      font-size: 15px;
      padding: 8px 12px;
      position: absolute;
      bottom: 8px;
      width: 100%;
      text-align: center;
    }
    /* 图片顺序的文本，(如，1/3) */

    .numbertext {
      color: #f2f2f2;
      font-size: 12px;
      padding: 8px 12px;
      position: absolute;
      top: 0;
    }
    /* 底部的指示按钮 */

    .dot {
      cursor: pointer;
      height: 13px;
      width: 13px;
      margin: 0 2px;
      background-color: #bbb;
      border-radius: 50%;
      display: inline-block;
      transition: background-color 0.6s ease;
    }

    .active,
    .dot:hover {
      background-color: #717171;
    }
    /* 淡入淡出的动画 */

    .fade {
      -webkit-animation-name: fade;
      -webkit-animation-duration: 1.5s;
      animation-name: fade;
      animation-duration: 1.5s;
    }

    @-webkit-keyframes fade {
      from {
        opacity: .4
      }
      to {
        opacity: 1
      }
    }

    @keyframes fade {
      from {
        opacity: .4
      }
      to {
        opacity: 1
      }
    }
  </style>
</head>
<body>

  <div class="slideshow-container">

    <div class="mySlides fade">
      <div class="numbertext">1 / 3</div>
      <img src="https://image-10001577.image.myqcloud.com/upload/3/20170428/14933734123710.jpg" style="width:100%">
      <div class="text">标题1</div>
    </div>

    <div class="mySlides fade">
      <div class="numbertext">2 / 3</div>
      <img src="https://image-10001577.image.myqcloud.com/upload/3/20170428/1493373435281.jpg" style="width:100%">
      <div class="text">标题2</div>
    </div>

    <div class="mySlides fade">
      <div class="numbertext">3 / 3</div>
      <img src="https://image-10001577.image.myqcloud.com/upload/3/20170428/14933734551830.jpg" style="width:100%">
      <div class="text">标题3</div>
    </div>

    <a class="prev" onclick="plusSlides(-1)">❮</a>
    <a class="next" onclick="plusSlides(1)">❯</a>

  </div>
  <br>

  <div style="text-align:center">
    <span class="dot" onclick="currentSlide(1)"></span>
    <span class="dot" onclick="currentSlide(2)"></span>
    <span class="dot" onclick="currentSlide(3)"></span>
  </div>

  <script>
    var slideIndex = 1;
    showSlides(slideIndex);

    function plusSlides(n) {
      showSlides(slideIndex += n);
    }

    function currentSlide(n) {
      showSlides(slideIndex = n);
    }

    function showSlides(n) {
      var i;
      var slides = document.getElementsByClassName("mySlides");
      var dots = document.getElementsByClassName("dot");
      if (n > slides.length) {
        slideIndex = 1
      }
      if (n < 1) {
        slideIndex = slides.length
      }
      for (i = 0; i < slides.length; i++) {
        slides[i].style.display = "none";
      }
      for (i = 0; i < dots.length; i++) {
        dots[i].className = dots[i].className.replace(" active", "");
      }
      slides[slideIndex - 1].style.display = "block";
      dots[slideIndex - 1].className += " active";
    }
  </script>

</body>
</html>

尝试一下 »

让幻灯片动起来

要让幻灯片自动切换，可以通过定时器来实现

<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <style>
    * {
      box-sizing: border-box
    }

    body {
      font-family: Verdana, sans-serif;
    }

    .mySlides {
      display: none
    }
    /* 轮播图容器 */

    .slideshow-container {
      max-width: 1000px;
      position: relative;
      margin: auto;
    }
    /* 上一张和下一张的按钮 */

    .prev,
    .next {
      cursor: pointer;
      position: absolute;
      top: 50%;
      width: auto;
      padding: 16px;
      margin-top: -22px;
      color: white;
      font-weight: bold;
      font-size: 18px;
      transition: 0.6s ease;
      border-radius: 0 3px 3px 0;
    }
    /* 将”下一张“的按钮定位在右边 */

    .next {
      right: 0;
      border-radius: 3px 0 0 3px;
    }
    /* 鼠标移到按钮上，增加一个有点透明的黑色背景 */

    .prev:hover,
    .next:hover {
      background-color: rgba(0, 0, 0, 0.8);
    }
    /* 标题的文本 */

    .text {
      color: #f2f2f2;
      font-size: 15px;
      padding: 8px 12px;
      position: absolute;
      bottom: 8px;
      width: 100%;
      text-align: center;
    }
    /* 图片顺序的文本，(如，1/3) */

    .numbertext {
      color: #f2f2f2;
      font-size: 12px;
      padding: 8px 12px;
      position: absolute;
      top: 0;
    }
    /* 底部的指示按钮 */

    .dot {
      cursor: pointer;
      height: 13px;
      width: 13px;
      margin: 0 2px;
      background-color: #bbb;
      border-radius: 50%;
      display: inline-block;
      transition: background-color 0.6s ease;
    }

    .active,
    .dot:hover {
      background-color: #717171;
    }
    /* 淡入淡出的动画 */

    .fade {
      -webkit-animation-name: fade;
      -webkit-animation-duration: 1.5s;
      animation-name: fade;
      animation-duration: 1.5s;
    }

    @-webkit-keyframes fade {
      from {
        opacity: .4
      }
      to {
        opacity: 1
      }
    }

    @keyframes fade {
      from {
        opacity: .4
      }
      to {
        opacity: 1
      }
    }
  </style>
</head>
<body>

  <h2>轮播图自动切换</h2>
  <p>每两秒更改到下一张图片：</p>

  <div class="slideshow-container">

    <div class="mySlides fade">
      <div class="numbertext">1 / 3</div>
      <img src="https://image-10001577.image.myqcloud.com/upload/3/20170428/14933734123710.jpg" style="width:100%">
      <div class="text">标题1</div>
    </div>

    <div class="mySlides fade">
      <div class="numbertext">2 / 3</div>
      <img src="https://image-10001577.image.myqcloud.com/upload/3/20170428/1493373435281.jpg" style="width:100%">
      <div class="text">标题2</div>
    </div>

    <div class="mySlides fade">
      <div class="numbertext">3 / 3</div>
      <img src="https://image-10001577.image.myqcloud.com/upload/3/20170428/14933734551830.jpg" style="width:100%">
      <div class="text">标题3</div>
    </div>

  </div>
  <br>

  <div style="text-align:center">
    <span class="dot"></span>
    <span class="dot"></span>
    <span class="dot"></span>
  </div>

  <script>
    var slideIndex = 0;
    showSlides();

    function showSlides() {
      var i;
      var slides = document.getElementsByClassName("mySlides");
      var dots = document.getElementsByClassName("dot");
      for (i = 0; i < slides.length; i++) {
        slides[i].style.display = "none";
      }
      slideIndex++;
      if (slideIndex > slides.length) {
        slideIndex = 1
      }
      for (i = 0; i < dots.length; i++) {
        dots[i].className = dots[i].className.replace(" active", "");
      }
      slides[slideIndex - 1].style.display = "block";
      dots[slideIndex - 1].className += " active";
      // 每两秒展示下一张图片
      setTimeout(showSlides, 2000);
    }
  </script>

</body>
</html>

尝试一下 »

如何实现轮播图 Slideshow

轮播图

轮播图有什么功能？

创建一个轮播图

步骤1，创建HTML

步骤2 添加CSS：

步骤3：增加JavaScript：

最终轮播图的效果如下

让幻灯片动起来

常见Web组件的实现

更多教程

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