为什么我的Bootstrap示例页面中的轮播无法正常工作？

如何解决为什么我的Bootstrap示例页面中的轮播无法正常工作？

我正在用Bootstrap创建一个网页，并且我想添加一个轮播。因此，我转到“示例”页面，并查找轮播模板（https://getbootstrap.com/docs/4.5/examples/carousel/）的源代码。我将轮播部分复制/粘贴到我的网页中，但无法正常工作。

carousel from bootsrap web page

carousel from my web page

如您所见，我只获得了原始轮播的一小部分，我也不知道为什么，因为它应该是Bootstrap轮播的原始源代码。这是我代码中与轮播相关的部分：

 <body>
    <?PHP include "header.PHP" ?>
    <main role="main">
     <div id="myCarousel" class="carousel slide" data-ride="carousel">
    <ol class="carousel-indicators">
      <li data-target="#myCarousel" data-slide-to="0" class="active"></li>
      <li data-target="#myCarousel" data-slide-to="1"></li>
      <li data-target="#myCarousel" data-slide-to="2"></li>
    </ol>
    <div class="carousel-inner">
      <div class="carousel-item active">
        <svg class="bd-placeholder-img" width="100%" height="100%" xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMidYMid slice" focusable="false" role="img"><rect width="100%" height="100%" fill="#777"/></svg>
        <div class="container">
          <div class="carousel-caption text-left">
            <h1>Example headline.</h1>
            <p>Cras justo odio,dapibus ac facilisis in,egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id dolor id nibh ultricies vehicula ut id elit.</p>
            <p><a class="btn btn-lg btn-primary" href="#" role="button">Sign up today</a></p>
          </div>
        </div>
      </div>
      <div class="carousel-item">
        <svg class="bd-placeholder-img" width="100%" height="100%" xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMidYMid slice" focusable="false" role="img"><rect width="100%" height="100%" fill="#777"/></svg>
        <div class="container">
          <div class="carousel-caption">
            <h1>Another example headline.</h1>
            <p>Cras justo odio,egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id dolor id nibh ultricies vehicula ut id elit.</p>
            <p><a class="btn btn-lg btn-primary" href="#" role="button">Learn more</a></p>
          </div>
        </div>
      </div>
      <div class="carousel-item">
        <svg class="bd-placeholder-img" width="100%" height="100%" xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMidYMid slice" focusable="false" role="img"><rect width="100%" height="100%" fill="#777"/></svg>
        <div class="container">
          <div class="carousel-caption text-right">
            <h1>One more for good measure.</h1>
            <p>Cras justo odio,egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id dolor id nibh ultricies vehicula ut id elit.</p>
            <p><a class="btn btn-lg btn-primary" href="#" role="button">browse gallery</a></p>
          </div>
        </div>
      </div>
    </div>
    <a class="carousel-control-prev" href="#myCarousel" role="button" data-slide="prev">
      <span class="carousel-control-prev-icon" aria-hidden="true"></span>
      <span class="sr-only">PrevIoUs</span>
    </a>
    <a class="carousel-control-next" href="#myCarousel" role="button" data-slide="next">
      <span class="carousel-control-next-icon" aria-hidden="true"></span>
      <span class="sr-only">Next</span>
    </a>
  </div>
</body>

解决方法

尝试在HTML body标签的末尾添加jquery插件和bootstrap js。您忘记添加jquery和bootstrap js，而没有添加此轮播将无法正常工作。如您所说，您是从该示例复制并粘贴的，所以我想您也忘记添加其自定义CSS

<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.1/dist/umd/popper.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" hre="https://getbootstrap.com/docs/4.5/examples/carousel/carousel.css">

使用jquery和bootstrap bundle插件，还添加自定义CSS。

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://getbootstrap.com/docs/4.5/dist/js/bootstrap.bundle.min.js"></script>
<link href="https://getbootstrap.com/docs/4.5/examples/carousel/carousel.css" rel="stylesheet"/>
<link href="https://getbootstrap.com/docs/4.5/dist/css/bootstrap.min.css" rel="stylesheet"/>

<body>
    <main role="main">
    <div id="myCarousel" class="carousel slide" data-ride="carousel">
        <ol class="carousel-indicators">
            <li data-target="#myCarousel" data-slide-to="0" class="active"></li>
            <li data-target="#myCarousel" data-slide-to="1"></li>
            <li data-target="#myCarousel" data-slide-to="2"></li>
        </ol>
        <div class="carousel-inner">
            <div class="carousel-item active">
                <svg class="bd-placeholder-img" width="100%" height="100%" xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMidYMid
                    slice" focusable="false" role="img">
                    <rect width="100%" height="100%"
                        fill="#777"/>
                </svg>
                <div class="container">
                    <div class="carousel-caption text-left">
                        <h1>Example headline.</h1>
                        <p>Cras justo odio,dapibus ac facilisis in,egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id
                            dolor id nibh ultricies vehicula ut id elit.
                        </p>
                        <p><a class="btn btn-lg btn-primary" href="#" role="button">Sign up today</a></p>
                    </div>
                </div>
            </div>
            <div class="carousel-item">
                <svg class="bd-placeholder-img" width="100%" height="100%" xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMidYMid
                    slice" focusable="false" role="img">
                    <rect width="100%" height="100%"
                        fill="#777"/>
                </svg>
                <div class="container">
                    <div class="carousel-caption">
                        <h1>Another example headline.</h1>
                        <p>Cras justo odio,egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id
                            dolor id nibh ultricies vehicula ut id elit.
                        </p>
                        <p><a class="btn btn-lg btn-primary" href="#" role="button">Learn more</a></p>
                    </div>
                </div>
            </div>
            <div class="carousel-item">
                <svg class="bd-placeholder-img" width="100%" height="100%" xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMidYMid
                    slice" focusable="false" role="img">
                    <rect width="100%" height="100%"
                        fill="#777"/>
                </svg>
                <div class="container">
                    <div class="carousel-caption text-right">
                        <h1>One more for good measure.</h1>           
                        <p>Cras justo odio,egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id
                            dolor id nibh ultricies vehicula ut id elit.
                        </p>
                        <p><a class="btn btn-lg btn-primary" href="#" role="button">Browse gallery</a></p>
                    </div>
                </div>
            </div>
        </div>
        <a class="carousel-control-prev" href="#myCarousel" role="button" data-slide="prev">
        <span class="carousel-control-prev-icon" aria-hidden="true"></span>
        <span class="sr-only">Previous</span>
        </a>
        <a class="carousel-control-next" href="#myCarousel" role="button" data-slide="next">
        <span class="carousel-control-next-icon" aria-hidden="true"></span>
        <span class="sr-only">Next</span>
        </a>   
    </div>
</body>