Carousel

用于循环播放元素（图片或文本幻灯片）的幻灯片组件，如轮播。

内容提要

工作原理

轮播是一个幻灯片，用于循环浏览一系列内容，使用 CSS 3D 转换(transforms)和一些 JavaScript 构建。它适用于一系列图片、文本或自定义标记。它还包括对上一个/下一个控件和指示器的支持。

在支持 Page Visibility API 的浏览器中，当网页对用户不可见时（例如当浏览器选项卡处于非活动状态时，浏览器窗口被最小化等），轮播将避免滑动。

该组件的动画效果依赖于 prefers-reduced-motion 媒体查询。请参阅无障碍文档的减少动画效果部分。

请注意，不支持嵌套轮播，并且轮播通常不符合无障碍标准。

示例

轮播不会自动标准化幻灯片尺寸。因此，您可能需要使用其他实用程序或自定义样式来适当调整内容的大小。虽然轮播支持上一个/下一个控件和指示器，但它们并不是明确要求的。根据需要添加和自定义。

.active 类需要添加到其中一张幻灯片，否则轮播将不可见。还要确保在 .carousel 上为可选控件设置唯一的 id，尤其是在单个页面上使用多个轮播时。控件和指示器元素必须具有与 .carousel 元素的 id 匹配的 data-bs-target 属性（或链接的 href）。

仅幻灯片

这是一个只有幻灯片的轮播图。请注意轮播图片上添加 .d-block 和 .w-100 类以防止浏览器默认图片对齐。

<div id="carouselExampleSlidesOnly" class="carousel slide" data-bs-ride="carousel">
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
  </div>
</div>

带控制按钮

添加上一个和下一个控件。我们建议使用 <button> 元素，但您也可以将 <a> 元素与 role="button" 一起使用。

<div id="carouselExampleControls" class="carousel slide" data-bs-ride="carousel">
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
  </div>
  <button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleControls" data-bs-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Previous</span>
  </button>
  <button class="carousel-control-next" type="button" data-bs-target="#carouselExampleControls" data-bs-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Next</span>
  </button>
</div>

带指示器

您还可以将指示器与控件一起添加到轮播中。

<div id="carouselExampleIndicators" class="carousel slide" data-bs-ride="carousel">
  <div class="carousel-indicators">
    <button type="button" data-bs-target="#carouselExampleIndicators" data-bs-slide-to="0" class="active" aria-current="true" aria-label="Slide 1"></button>
    <button type="button" data-bs-target="#carouselExampleIndicators" data-bs-slide-to="1" aria-label="Slide 2"></button>
    <button type="button" data-bs-target="#carouselExampleIndicators" data-bs-slide-to="2" aria-label="Slide 3"></button>
  </div>
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
  </div>
  <button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleIndicators" data-bs-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Previous</span>
  </button>
  <button class="carousel-control-next" type="button" data-bs-target="#carouselExampleIndicators" data-bs-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Next</span>
  </button>
</div>

带标题

使用任何 .carousel-item 中的 .carousel-caption 元素轻松为幻灯片添加标题。它们可以通过可选的显示实用程序轻松隐藏在较小的视口中的显示，如下所示。我们最初使用 .d-none 隐藏它们，然后使用 .d-md-block 将它们重新在中型设备中显示。

First slide label

Some representative placeholder content for the first slide.

Second slide label

Some representative placeholder content for the second slide.

Third slide label

Some representative placeholder content for the third slide.

<div id="carouselExampleCaptions" class="carousel slide" data-bs-ride="carousel">
  <div class="carousel-indicators">
    <button type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide-to="0" class="active" aria-current="true" aria-label="Slide 1"></button>
    <button type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide-to="1" aria-label="Slide 2"></button>
    <button type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide-to="2" aria-label="Slide 3"></button>
  </div>
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="..." class="d-block w-100" alt="...">
      <div class="carousel-caption d-none d-md-block">
        <h5>First slide label</h5>
        <p>Some representative placeholder content for the first slide.</p>
      </div>
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
      <div class="carousel-caption d-none d-md-block">
        <h5>Second slide label</h5>
        <p>Some representative placeholder content for the second slide.</p>
      </div>
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
      <div class="carousel-caption d-none d-md-block">
        <h5>Third slide label</h5>
        <p>Some representative placeholder content for the third slide.</p>
      </div>
    </div>
  </div>
  <button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Previous</span>
  </button>
  <button class="carousel-control-next" type="button" data-bs-target="#carouselExampleCaptions" data-bs-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Next</span>
  </button>
</div>

淡入淡出

将 .carousel-fade 添加到轮播中，以使用淡入淡出过渡而不是默认为轮播图制作动画。

<div id="carouselExampleFade" class="carousel slide carousel-fade" data-bs-ride="carousel">
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
  </div>
  <button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleFade" data-bs-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Previous</span>
  </button>
  <button class="carousel-control-next" type="button" data-bs-target="#carouselExampleFade" data-bs-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Next</span>
  </button>
</div>

单个 .carousel-item 的间隔 interval

将 data-bs-interval="" 添加到 .carousel-item 以更改自动循环到下一个项目之间的延迟时间。

<div id="carouselExampleInterval" class="carousel slide" data-bs-ride="carousel">
  <div class="carousel-inner">
    <div class="carousel-item active" data-bs-interval="10000">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item" data-bs-interval="2000">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
  </div>
  <button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleInterval" data-bs-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Previous</span>
  </button>
  <button class="carousel-control-next" type="button" data-bs-target="#carouselExampleInterval" data-bs-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Next</span>
  </button>
</div>

禁用触摸滑动

轮播支持在触摸屏设备上向左/向右滑动以在幻灯片之间移动。可以使用 data-bs-touch 属性禁用触摸滑动。下面的示例也不包含 data-bs-ride 属性并且具有 data-bs-interval="false" 因此它不会自动播放。

<div id="carouselExampleControlsNoTouching" class="carousel slide" data-bs-touch="false" data-bs-interval="false">
  <div class="carousel-inner">
    <div class="carousel-item active">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
    </div>
  </div>
  <button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleControlsNoTouching" data-bs-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Previous</span>
  </button>
  <button class="carousel-control-next" type="button" data-bs-target="#carouselExampleControlsNoTouching" data-bs-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Next</span>
  </button>
</div>

暗黑变体

将 .carousel-dark 添加到 .carousel 以获得更暗的控件、指示器和标题。控件已使用 filter CSS 属性从其默认的白色填充反转。标题和控件具有自定义 color 和 background-color 的附加 Sass 变量。

First slide label

Some representative placeholder content for the first slide.

Second slide label

Some representative placeholder content for the second slide.

Third slide label

Some representative placeholder content for the third slide.

<div id="carouselExampleDark" class="carousel carousel-dark slide" data-bs-ride="carousel">
  <div class="carousel-indicators">
    <button type="button" data-bs-target="#carouselExampleDark" data-bs-slide-to="0" class="active" aria-current="true" aria-label="Slide 1"></button>
    <button type="button" data-bs-target="#carouselExampleDark" data-bs-slide-to="1" aria-label="Slide 2"></button>
    <button type="button" data-bs-target="#carouselExampleDark" data-bs-slide-to="2" aria-label="Slide 3"></button>
  </div>
  <div class="carousel-inner">
    <div class="carousel-item active" data-bs-interval="10000">
      <img src="..." class="d-block w-100" alt="...">
      <div class="carousel-caption d-none d-md-block">
        <h5>First slide label</h5>
        <p>Some representative placeholder content for the first slide.</p>
      </div>
    </div>
    <div class="carousel-item" data-bs-interval="2000">
      <img src="..." class="d-block w-100" alt="...">
      <div class="carousel-caption d-none d-md-block">
        <h5>Second slide label</h5>
        <p>Some representative placeholder content for the second slide.</p>
      </div>
    </div>
    <div class="carousel-item">
      <img src="..." class="d-block w-100" alt="...">
      <div class="carousel-caption d-none d-md-block">
        <h5>Third slide label</h5>
        <p>Some representative placeholder content for the third slide.</p>
      </div>
    </div>
  </div>
  <button class="carousel-control-prev" type="button" data-bs-target="#carouselExampleDark" data-bs-slide="prev">
    <span class="carousel-control-prev-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Previous</span>
  </button>
  <button class="carousel-control-next" type="button" data-bs-target="#carouselExampleDark" data-bs-slide="next">
    <span class="carousel-control-next-icon" aria-hidden="true"></span>
    <span class="visually-hidden">Next</span>
  </button>
</div>

自定义过渡

.carousel-item 的过渡持续时间可以在编译之前使用 $carousel-transition-duration Sass 变量进行更改。或者如果您使用已编译的 CSS，则可以自定义样式。如果应用了多个转换，请确保首先定义transform transition（例如。transition: transform 2s ease, opacity .5s ease-out）。

Sass

变量

$carousel-control-color:             $white;
$carousel-control-width:             15%;
$carousel-control-opacity:           .5;
$carousel-control-hover-opacity:     .9;
$carousel-control-transition:        opacity .15s ease;

$carousel-indicator-width:           30px;
$carousel-indicator-height:          3px;
$carousel-indicator-hit-area-height: 10px;
$carousel-indicator-spacer:          3px;
$carousel-indicator-opacity:         .5;
$carousel-indicator-active-bg:       $white;
$carousel-indicator-active-opacity:  1;
$carousel-indicator-transition:      opacity .6s ease;

$carousel-caption-width:             70%;
$carousel-caption-color:             $white;
$carousel-caption-padding-y:         1.25rem;
$carousel-caption-spacer:            1.25rem;

$carousel-control-icon-width:        2rem;

$carousel-control-prev-icon-bg:      url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='#{$carousel-control-color}'><path d='M11.354 1.646a.5.5 0 0 1 0 .708L5.707 8l5.647 5.646a.5.5 0 0 1-.708.708l-6-6a.5.5 0 0 1 0-.708l6-6a.5.5 0 0 1 .708 0z'/></svg>");
$carousel-control-next-icon-bg:      url("data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16' fill='#{$carousel-control-color}'><path d='M4.646 1.646a.5.5 0 0 1 .708 0l6 6a.5.5 0 0 1 0 .708l-6 6a.5.5 0 0 1-.708-.708L10.293 8 4.646 2.354a.5.5 0 0 1 0-.708z'/></svg>");

$carousel-transition-duration:       .6s;
$carousel-transition:                transform $carousel-transition-duration ease-in-out; // Define transform transition first if using multiple transitions (e.g., `transform 2s ease, opacity .5s ease-out`)

$carousel-dark-indicator-active-bg:  $black;
$carousel-dark-caption-color:        $black;
$carousel-dark-control-icon-filter:  invert(1) grayscale(100);

用法

通过数据属性

使用数据属性轻松控制轮播的位置。 data-bs-slide 接受关键字 prev 或 next，这会改变相对于当前位置的幻灯片位置。或者，使用 data-bs-slide-to 将原始幻灯片索引传递给轮播 data-bs-slide-to="2"，这会移动幻灯片位置到以 0 开头的特定索引。

data-bs-ride="carousel" 属性用于将轮播标记为在页面加载时开始动画。如果你不使用 data-bs-ride="carousel" 来初始化你的轮播，你必须自己初始化它。 它不能与同一轮播的显式 JavaScript 初始化结合使用。

通过 JavaScript

手动调用轮播：

var myCarousel = document.querySelector('#myCarousel')
var carousel = new bootstrap.Carousel(myCarousel)

选项

选项可以通过数据属性或 JavaScript 传递。对于数据属性，将选项名称附加到 data-bs-，如 data-bs-interval=""。

名称	类型	默认值	描述
`interval`	number	`5000`	自动循环项目之间的延迟时间。如果`false`，轮播不会自动循环。
`keyboard`	boolean	`true`	Whether the carousel should react to keyboard events.
`pause`	string \| boolean	`'hover'`	If set to `'hover'`, pauses the cycling of the carousel on `mouseenter` and resumes the cycling of the carousel on `mouseleave`. If set to `false`, hovering over the carousel won't pause it. On touch-enabled devices, when set to `'hover'`, cycling will pause on `touchend` (once the user finished interacting with the carousel) for two intervals, before automatically resuming. Note that this is in addition to the above mouse behavior.
`ride`	string \| boolean	`false`	Autoplays the carousel after the user manually cycles the first item. If set to `'carousel'`, autoplays the carousel on load.
`wrap`	boolean	`true`	Whether the carousel should cycle continuously or have hard stops.
`touch`	boolean	`true`	Whether the carousel should support left/right swipe interactions on touchscreen devices.

Methods

Asynchronous methods and transitions

All API methods are asynchronous and start a transition. They return to the caller as soon as the transition is started but before it ends. In addition, a method call on a transitioning component will be ignored.

See our JavaScript documentation for more information.

You can create a carousel instance with the carousel constructor, for example, to initialize with additional options and start cycling through items:

var myCarousel = document.querySelector('#myCarousel')
var carousel = new bootstrap.Carousel(myCarousel, {
  interval: 2000,
  wrap: false
})

Method	Description
`cycle`	Cycles through the carousel items from left to right.
`pause`	Stops the carousel from cycling through items.
`prev`	Cycles to the previous item. Returns to the caller before the previous item has been shown (e.g., before the `slid.bs.carousel` event occurs).
`next`	Cycles to the next item. Returns to the caller before the next item has been shown (e.g., before the `slid.bs.carousel` event occurs).
`nextWhenVisible`	Don't cycle carousel to next when the page isn't visible or the carousel or its parent isn't visible. Returns to the caller before the target item has been shown
`to`	Cycles the carousel to a particular frame (0 based, similar to an array). Returns to the caller before the target item has been shown (e.g., before the `slid.bs.carousel` event occurs).
`dispose`	Destroys an element's carousel. (Removes stored data on the DOM element)
`getInstance`	Static method which allows you to get the carousel instance associated to a DOM element, you can use it like this: `bootstrap.Carousel.getInstance(element)`
`getOrCreateInstance`	Static method which returns a carousel instance associated to a DOM element or create a new one in case it wasn't initialized. You can use it like this: `bootstrap.Carousel.getOrCreateInstance(element)`

Events

Bootstrap’s carousel class exposes two events for hooking into carousel functionality. Both events have the following additional properties:

direction: The direction in which the carousel is sliding (either "left" or "right").
relatedTarget: The DOM element that is being slid into place as the active item.
from: The index of the current item
to: The index of the next item

All carousel events are fired at the carousel itself (i.e. at the <div class="carousel">).

Event type	Description
`slide.bs.carousel`	Fires immediately when the `slide` instance method is invoked.
`slid.bs.carousel`	Fired when the carousel has completed its slide transition.

var myCarousel = document.getElementById('myCarousel')

myCarousel.addEventListener('slide.bs.carousel', function () {
  // do something...
})