按钮

使用 Bootstrap 的自定义按钮样式，用于表单、对话框等中的操作，并支持多种尺寸、状态等。

基类

🌐 Base class

Bootstrap 有一个基础 .btn 类，用于设置基本样式，例如内边距和内容对齐。默认情况下，.btn 控件具有透明的边框和背景颜色，并且没有任何明确的聚焦和悬停样式。

🌐 Bootstrap has a base .btn class that sets up basic styles such as padding and content alignment. By default, .btn controls have a transparent border and background color, and lack any explicit focus and hover styles.

html

<button type="button" class="btn">Base class</button>

.btn 类旨在与我们的按钮变体一起使用，或作为你自定义样式的基础。

🌐 The .btn class is intended to be used in conjunction with our button variants, or to serve as a basis for your own custom styles.

如果你单独使用 .btn 类，请记得至少定义一些明确的 :focus 和/或 :focus-visible 样式。

变体

🌐 Variants

Bootstrap 包括几个按钮变体，每个变体都有自己的语义目的，并添加了一些额外的功能以实现更多控制。

🌐 Bootstrap includes several button variants, each serving its own semantic purpose, with a few extras thrown in for more control.

html

<button type="button" class="btn btn-primary">Primary</button>
<button type="button" class="btn btn-secondary">Secondary</button>
<button type="button" class="btn btn-success">Success</button>
<button type="button" class="btn btn-danger">Danger</button>
<button type="button" class="btn btn-warning">Warning</button>
<button type="button" class="btn btn-info">Info</button>
<button type="button" class="btn btn-light">Light</button>
<button type="button" class="btn btn-dark">Dark</button>

<button type="button" class="btn btn-link">Link</button>

Accessibility tip: Using color to add meaning only provides a visual indication, which will not be conveyed to users of assistive technologies like screen readers. Please ensure the meaning is obvious from the content itself (e.g., the visible text with a sufficient color contrast) or is included through alternative means, such as additional text hidden with the .visually-hidden class.

禁用文本换行

🌐 Disable text wrapping

如果你不希望按钮文字换行，你可以将 .text-nowrap 类添加到按钮。在 Sass 中，你可以设置 $btn-white-space: nowrap 来禁用每个按钮的文字换行。

🌐 If you don’t want the button text to wrap, you can add the .text-nowrap class to the button. In Sass, you can set $btn-white-space: nowrap to disable text wrapping for each button.

按钮标签

🌐 Button tags

.btn 类设计用于与 <button> 元素一起使用。然而，你也可以在 <a> 或 <input> 元素上使用这些类（尽管某些浏览器可能会应用略有不同的渲染）。

🌐 The .btn classes are designed to be used with the <button> element. However, you can also use these classes on <a> or <input> elements (though some browsers may apply a slightly different rendering).

在 <a> 元素上使用按钮类时，这些元素用于触发页面内功能（如折叠内容），而不是链接到新页面或当前页面中的其他部分，这些链接应被赋予 role="button"，以便向屏幕阅读器等辅助技术适当地传达它们的用途。

🌐 When using button classes on <a> elements that are used to trigger in-page functionality (like collapsing content), rather than linking to new pages or sections within the current page, these links should be given a role="button" to appropriately convey their purpose to assistive technologies such as screen readers.

Link

html

<a class="btn btn-primary" href="#" role="button">Link</a>
<button class="btn btn-primary" type="submit">Button</button>
<input class="btn btn-primary" type="button" value="Input">
<input class="btn btn-primary" type="submit" value="Submit">
<input class="btn btn-primary" type="reset" value="Reset">

轮廓按钮

🌐 Outline buttons

需要一个按钮，但不想要它们带来的沉重背景色？将默认的修饰类替换为 .btn-outline-* 类，以移除任何按钮的所有背景图片和颜色。

🌐 In need of a button, but not the hefty background colors they bring? Replace the default modifier classes with the .btn-outline-* ones to remove all background images and colors on any button.

html

<button type="button" class="btn btn-outline-primary">Primary</button>
<button type="button" class="btn btn-outline-secondary">Secondary</button>
<button type="button" class="btn btn-outline-success">Success</button>
<button type="button" class="btn btn-outline-danger">Danger</button>
<button type="button" class="btn btn-outline-warning">Warning</button>
<button type="button" class="btn btn-outline-info">Info</button>
<button type="button" class="btn btn-outline-light">Light</button>
<button type="button" class="btn btn-outline-dark">Dark</button>

一些按钮样式使用相对较浅的前景色，因此应仅在深色背景上使用，以确保有足够的对比度。

尺寸

🌐 Sizes

想要更大或更小的按钮吗？添加 .btn-lg 或 .btn-sm 来获取其他尺寸。

🌐 Fancy larger or smaller buttons? Add .btn-lg or .btn-sm for additional sizes.

html

<button type="button" class="btn btn-primary btn-lg">Large button</button>
<button type="button" class="btn btn-secondary btn-lg">Large button</button>

html

<button type="button" class="btn btn-primary btn-sm">Small button</button>
<button type="button" class="btn btn-secondary btn-sm">Small button</button>

你甚至可以使用 CSS 变量来调整自己的自定义大小：

🌐 You can even roll your own custom sizing with CSS variables:

html

<button type="button" class="btn btn-primary"
        style="--bs-btn-padding-y: .25rem; --bs-btn-padding-x: .5rem; --bs-btn-font-size: .75rem;">
  Custom button
</button>

禁用状态

🌐 Disabled state

通过向任何 <button> 元素添加 disabled 布尔属性，使按钮看起来处于非活动状态。禁用的按钮应用了 pointer-events: none，防止触发悬停和激活状态。

🌐 Make buttons look inactive by adding the disabled boolean attribute to any <button> element. Disabled buttons have pointer-events: none applied to, preventing hover and active states from triggering.

html

<button type="button" class="btn btn-primary" disabled>Primary button</button>
<button type="button" class="btn btn-secondary" disabled>Button</button>
<button type="button" class="btn btn-outline-primary" disabled>Primary button</button>
<button type="button" class="btn btn-outline-secondary" disabled>Button</button>

使用 <a> 元素的禁用按钮行为有些不同：

🌐 Disabled buttons using the <a> element behave a bit different:

<a>不支持disabled属性，因此你必须添加.disabled类才能让其在视觉上显示为禁用。
包括一些面向未来的样式以禁用锚点按钮上的所有 pointer-events。
使用 <a> 的禁用按钮应包含 aria-disabled="true" 属性，以向辅助技术指示元素的状态。
使用 <a> 的禁用按钮不应包含 href 属性。

Primary link Link

html

<a class="btn btn-primary disabled" role="button" aria-disabled="true">Primary link</a>
<a class="btn btn-secondary disabled" role="button" aria-disabled="true">Link</a>

链接功能警告

🌐 Link functionality caveat

为了应对必须在禁用链接上保留 href 属性的情况，.disabled 类使用 pointer-events: none 尝试禁用 <a> 的链接功能。请注意，这个 CSS 属性还未在 HTML 中标准化，但所有现代浏览器都支持它。此外，即使在支持 pointer-events: none 的浏览器中，键盘导航仍然不会受到影响，这意味着有视力的键盘用户和使用辅助技术的用户仍然可以激活这些链接。因此，为了安全起见，除了 aria-disabled="true" 外，还应在这些链接上添加 tabindex="-1" 属性，以防止它们获得键盘焦点，并使用自定义 JavaScript 完全禁用它们的功能。

🌐 To cover cases where you have to keep the href attribute on a disabled link, the .disabled class uses pointer-events: none to try to disable the link functionality of <a>s. Note that this CSS property is not yet standardized for HTML, but all modern browsers support it. In addition, even in browsers that do support pointer-events: none, keyboard navigation remains unaffected, meaning that sighted keyboard users and users of assistive technologies will still be able to activate these links. So to be safe, in addition to aria-disabled="true", also include a tabindex="-1" attribute on these links to prevent them from receiving keyboard focus, and use custom JavaScript to disable their functionality altogether.

Primary link Link

html

<a href="#" class="btn btn-primary disabled" tabindex="-1" role="button" aria-disabled="true">Primary link</a>
<a href="#" class="btn btn-secondary disabled" tabindex="-1" role="button" aria-disabled="true">Link</a>

块按钮

🌐 Block buttons

创建响应式全宽“块按钮”堆栈，就像 Bootstrap 4 中的那些一样，同时结合使用我们的显示和间距工具类。通过使用工具类而不是按钮特定的类，我们可以更好地控制间距、对齐和响应式行为。

🌐 Create responsive stacks of full-width, “block buttons” like those in Bootstrap 4 with a mix of our display and gap utilities. By using utilities instead of button-specific classes, we have much greater control over spacing, alignment, and responsive behaviors.

html

<div class="d-grid gap-2">
  <button class="btn btn-primary" type="button">Button</button>
  <button class="btn btn-primary" type="button">Button</button>
</div>

在这里，我们创建了一个响应式变体，从垂直堆叠的按钮开始，直到 md 断点，在该断点处，.d-md-block 替换 .d-grid 类，从而使 gap-2 实用程序无效。调整你的浏览器大小以查看它们的变化。

🌐 Here we create a responsive variation, starting with vertically stacked buttons until the md breakpoint, where .d-md-block replaces the .d-grid class, thus nullifying the gap-2 utility. Resize your browser to see them change.

html

<div class="d-grid gap-2 d-md-block">
  <button class="btn btn-primary" type="button">Button</button>
  <button class="btn btn-primary" type="button">Button</button>
</div>

你可以使用网格列宽类来调整块按钮的宽度。例如，对于半宽的“块按钮”，使用 .col-6。也可以使用 .mx-auto 将其水平居中。

🌐 You can adjust the width of your block buttons with grid column width classes. For example, for a half-width “block button”, use .col-6. Center it horizontally with .mx-auto, too.

html

<div class="d-grid gap-2 col-6 mx-auto">
  <button class="btn btn-primary" type="button">Button</button>
  <button class="btn btn-primary" type="button">Button</button>
</div>

可以使用额外的工具类来调整按钮水平排列时的对齐方式。在这里，我们采用了之前的响应式示例，并在按钮上添加了一些弹性布局工具类和边距工具类，以便在按钮不再堆叠时将它们右对齐。

🌐 Additional utilities can be used to adjust the alignment of buttons when horizontal. Here we’ve taken our previous responsive example and added some flex utilities and a margin utility on the button to right-align the buttons when they’re no longer stacked.

html

<div class="d-grid gap-2 d-md-flex justify-content-md-end">
  <button class="btn btn-primary me-md-2" type="button">Button</button>
  <button class="btn btn-primary" type="button">Button</button>
</div>

按钮插件

🌐 Button plugin

按钮插件允许你创建简单的开/关切换按钮。

🌐 The button plugin allows you to create simple on/off toggle buttons.

在视觉上，这些切换按钮与复选框切换按钮完全相同。然而，它们在辅助技术中的渲染方式不同：复选框切换按钮会被屏幕阅读器宣布为“已选中”/“未选中”（因为尽管外观相同，它们本质上仍然是复选框），而这些切换按钮会被宣布为“按钮”/“按钮已按下”。在这两种方法之间的选择取决于你创建的切换类型，以及当作为复选框或实际按钮宣布时，切换是否对用户有意义。

切换状态

🌐 Toggle states

添加 data-bs-toggle="button" 以切换按钮的 active 状态。如果你在预先切换按钮，则必须手动添加 .active 类并且 aria-pressed="true"，以确保它被适当地传达给辅助技术。

🌐 Add data-bs-toggle="button" to toggle a button’s active state. If you’re pre-toggling a button, you must manually add the .active class and aria-pressed="true" to ensure that it is conveyed appropriately to assistive technologies.

html

<p class="d-inline-flex gap-1">
  <button type="button" class="btn" data-bs-toggle="button">Toggle button</button>
  <button type="button" class="btn active" data-bs-toggle="button" aria-pressed="true">Active toggle button</button>
  <button type="button" class="btn" disabled data-bs-toggle="button">Disabled toggle button</button>
</p>
<p class="d-inline-flex gap-1">
  <button type="button" class="btn btn-primary" data-bs-toggle="button">Toggle button</button>
  <button type="button" class="btn btn-primary active" data-bs-toggle="button" aria-pressed="true">Active toggle button</button>
  <button type="button" class="btn btn-primary" disabled data-bs-toggle="button">Disabled toggle button</button>
</p>

Toggle link Active toggle link Disabled toggle link

html

<p class="d-inline-flex gap-1">
  <a href="#" class="btn" role="button" data-bs-toggle="button">Toggle link</a>
  <a href="#" class="btn active" role="button" data-bs-toggle="button" aria-pressed="true">Active toggle link</a>
  <a class="btn disabled" aria-disabled="true" role="button" data-bs-toggle="button">Disabled toggle link</a>
</p>
<p class="d-inline-flex gap-1">
  <a href="#" class="btn btn-primary" role="button" data-bs-toggle="button">Toggle link</a>
  <a href="#" class="btn btn-primary active" role="button" data-bs-toggle="button" aria-pressed="true">Active toggle link</a>
  <a class="btn btn-primary disabled" aria-disabled="true" role="button" data-bs-toggle="button">Disabled toggle link</a>
</p>

方法

🌐 Methods

你可以使用按钮构造函数创建按钮实例，例如：

🌐 You can create a button instance with the button constructor, for example:

const bsButton = new bootstrap.Button('#myButton')

方法	描述
`dispose`	销毁元素的按钮。（删除 DOM 元素上存储的数据）
`getInstance`	静态方法，允许你获取与 DOM 元素关联的按钮实例，你可以这样使用它：`bootstrap.Button.getInstance(element)`。
`getOrCreateInstance`	静态方法，返回与 DOM 元素关联的按钮实例，如果未初始化则会创建一个新的。你可以这样使用它：`bootstrap.Button.getOrCreateInstance(element)`。
`toggle`	切换按压状态。使按钮看起来像已被激活。

例如，切换所有按钮

🌐 For example, to toggle all buttons

document.querySelectorAll('.btn').forEach(buttonElement => {
  const button = bootstrap.Button.getOrCreateInstance(buttonElement)
  button.toggle()
})

CSS

变量

🌐 Variables

Added in v5.2.0

作为 Bootstrap 不断发展的 CSS 变量方法的一部分，按钮现在在 .btn 上使用本地 CSS 变量，以增强实时定制。CSS 变量的值通过 Sass 设置，因此仍然支持 Sass 定制。

🌐 As part of Bootstrap’s evolving CSS variables approach, buttons now use local CSS variables on .btn for enhanced real-time customization. Values for the CSS variables are set via Sass, so Sass customization is still supported, too.

scss/_buttons.scss

--#{$prefix}btn-padding-x: #{$btn-padding-x};
--#{$prefix}btn-padding-y: #{$btn-padding-y};
--#{$prefix}btn-font-family: #{$btn-font-family};
@include rfs($btn-font-size, --#{$prefix}btn-font-size);
--#{$prefix}btn-font-weight: #{$btn-font-weight};
--#{$prefix}btn-line-height: #{$btn-line-height};
--#{$prefix}btn-color: #{$btn-color};
--#{$prefix}btn-bg: transparent;
--#{$prefix}btn-border-width: #{$btn-border-width};
--#{$prefix}btn-border-color: transparent;
--#{$prefix}btn-border-radius: #{$btn-border-radius};
--#{$prefix}btn-hover-border-color: transparent;
--#{$prefix}btn-box-shadow: #{$btn-box-shadow};
--#{$prefix}btn-disabled-opacity: #{$btn-disabled-opacity};
--#{$prefix}btn-focus-box-shadow: 0 0 0 #{$btn-focus-width} rgba(var(--#{$prefix}btn-focus-shadow-rgb), .5);

每个 .btn-* 修饰符类都会更新相应的 CSS 变量，以在使用我们的 button-variant()、button-outline-variant() 和 button-size() 混入时最小化额外的 CSS 规则。

🌐 Each .btn-* modifier class updates the appropriate CSS variables to minimize additional CSS rules with our button-variant(), button-outline-variant(), and button-size() mixins.

这里是一个构建自定义 .btn-* 修饰符类的示例，就像我们为文档中特有的按钮所做的那样，通过重新分配 Bootstrap 的 CSS 变量，并混合使用我们自己的 CSS 和 Sass 变量。

🌐 Here’s an example of building a custom .btn-* modifier class as we do for the buttons unique to our docs by reassigning Bootstrap’s CSS variables with a mixture of our own CSS and Sass variables.

site/src/scss/_buttons.scss

.btn-bd-primary {
  --bs-btn-font-weight: 600;
  --bs-btn-color: var(--bs-white);
  --bs-btn-bg: var(--bd-violet-bg);
  --bs-btn-border-color: var(--bd-violet-bg);
  --bs-btn-hover-color: var(--bs-white);
  --bs-btn-hover-bg: #{shade-color($bd-violet, 10%)};
  --bs-btn-hover-border-color: #{shade-color($bd-violet, 10%)};
  --bs-btn-focus-shadow-rgb: var(--bd-violet-rgb);
  --bs-btn-active-color: var(--bs-btn-hover-color);
  --bs-btn-active-bg: #{shade-color($bd-violet, 20%)};
  --bs-btn-active-border-color: #{shade-color($bd-violet, 20%)};
}

Sass 变量

🌐 Sass variables

scss/_variables.scss

$btn-color:                   var(--#{$prefix}body-color);
$btn-padding-y:               $input-btn-padding-y;
$btn-padding-x:               $input-btn-padding-x;
$btn-font-family:             $input-btn-font-family;
$btn-font-size:               $input-btn-font-size;
$btn-line-height:             $input-btn-line-height;
$btn-white-space:             null; // Set to `nowrap` to prevent text wrapping

$btn-padding-y-sm:            $input-btn-padding-y-sm;
$btn-padding-x-sm:            $input-btn-padding-x-sm;
$btn-font-size-sm:            $input-btn-font-size-sm;

$btn-padding-y-lg:            $input-btn-padding-y-lg;
$btn-padding-x-lg:            $input-btn-padding-x-lg;
$btn-font-size-lg:            $input-btn-font-size-lg;

$btn-border-width:            $input-btn-border-width;

$btn-font-weight:             $font-weight-normal;
$btn-box-shadow:              inset 0 1px 0 rgba($white, .15), 0 1px 1px rgba($black, .075);
$btn-focus-width:             $input-btn-focus-width;
$btn-focus-box-shadow:        $input-btn-focus-box-shadow;
$btn-disabled-opacity:        .65;
$btn-active-box-shadow:       inset 0 3px 5px rgba($black, .125);

$btn-link-color:              var(--#{$prefix}link-color);
$btn-link-hover-color:        var(--#{$prefix}link-hover-color);
$btn-link-disabled-color:     $gray-600;
$btn-link-focus-shadow-rgb:   to-rgb(mix(color-contrast($link-color), $link-color, 15%));

// Allows for customizing button radius independently from global border radius
$btn-border-radius:           var(--#{$prefix}border-radius);
$btn-border-radius-sm:        var(--#{$prefix}border-radius-sm);
$btn-border-radius-lg:        var(--#{$prefix}border-radius-lg);

$btn-transition:              color .15s ease-in-out, background-color .15s ease-in-out, border-color .15s ease-in-out, box-shadow .15s ease-in-out;

$btn-hover-bg-shade-amount:       15%;
$btn-hover-bg-tint-amount:        15%;
$btn-hover-border-shade-amount:   20%;
$btn-hover-border-tint-amount:    10%;
$btn-active-bg-shade-amount:      20%;
$btn-active-bg-tint-amount:       20%;
$btn-active-border-shade-amount:  25%;
$btn-active-border-tint-amount:   10%;

Sass 混入

🌐 Sass mixins

按钮有三个 mixin：按钮和按钮轮廓变体 mixin（都基于 $theme-colors），以及一个按钮尺寸 mixin。

🌐 There are three mixins for buttons: button and button outline variant mixins (both based on $theme-colors), plus a button size mixin.

scss/mixins/_buttons.scss

@mixin button-variant(
  $background,
  $border,
  $color: color-contrast($background),
  $hover-background: if($color == $color-contrast-light, shade-color($background, $btn-hover-bg-shade-amount), tint-color($background, $btn-hover-bg-tint-amount)),
  $hover-border: if($color == $color-contrast-light, shade-color($border, $btn-hover-border-shade-amount), tint-color($border, $btn-hover-border-tint-amount)),
  $hover-color: color-contrast($hover-background),
  $active-background: if($color == $color-contrast-light, shade-color($background, $btn-active-bg-shade-amount), tint-color($background, $btn-active-bg-tint-amount)),
  $active-border: if($color == $color-contrast-light, shade-color($border, $btn-active-border-shade-amount), tint-color($border, $btn-active-border-tint-amount)),
  $active-color: color-contrast($active-background),
  $disabled-background: $background,
  $disabled-border: $border,
  $disabled-color: color-contrast($disabled-background)
) {
  --#{$prefix}btn-color: #{$color};
  --#{$prefix}btn-bg: #{$background};
  --#{$prefix}btn-border-color: #{$border};
  --#{$prefix}btn-hover-color: #{$hover-color};
  --#{$prefix}btn-hover-bg: #{$hover-background};
  --#{$prefix}btn-hover-border-color: #{$hover-border};
  --#{$prefix}btn-focus-shadow-rgb: #{to-rgb(mix($color, $border, 15%))};
  --#{$prefix}btn-active-color: #{$active-color};
  --#{$prefix}btn-active-bg: #{$active-background};
  --#{$prefix}btn-active-border-color: #{$active-border};
  --#{$prefix}btn-active-shadow: #{$btn-active-box-shadow};
  --#{$prefix}btn-disabled-color: #{$disabled-color};
  --#{$prefix}btn-disabled-bg: #{$disabled-background};
  --#{$prefix}btn-disabled-border-color: #{$disabled-border};
}

scss/mixins/_buttons.scss

@mixin button-outline-variant(
  $color,
  $color-hover: color-contrast($color),
  $active-background: $color,
  $active-border: $color,
  $active-color: color-contrast($active-background)
) {
  --#{$prefix}btn-color: #{$color};
  --#{$prefix}btn-border-color: #{$color};
  --#{$prefix}btn-hover-color: #{$color-hover};
  --#{$prefix}btn-hover-bg: #{$active-background};
  --#{$prefix}btn-hover-border-color: #{$active-border};
  --#{$prefix}btn-focus-shadow-rgb: #{to-rgb($color)};
  --#{$prefix}btn-active-color: #{$active-color};
  --#{$prefix}btn-active-bg: #{$active-background};
  --#{$prefix}btn-active-border-color: #{$active-border};
  --#{$prefix}btn-active-shadow: #{$btn-active-box-shadow};
  --#{$prefix}btn-disabled-color: #{$color};
  --#{$prefix}btn-disabled-bg: transparent;
  --#{$prefix}btn-disabled-border-color: #{$color};
  --#{$prefix}gradient: none;
}

scss/mixins/_buttons.scss

@mixin button-size($padding-y, $padding-x, $font-size, $border-radius) {
  --#{$prefix}btn-padding-y: #{$padding-y};
  --#{$prefix}btn-padding-x: #{$padding-x};
  @include rfs($font-size, --#{$prefix}btn-font-size);
  --#{$prefix}btn-border-radius: #{$border-radius};
}

Sass 循环

🌐 Sass loops

按钮变体（用于普通按钮和轮廓按钮）使用各自的 mixin，并结合我们的 $theme-colors 映射在 scss/_buttons.scss 中生成修饰类。

🌐 Button variants (for regular and outline buttons) use their respective mixins with our $theme-colors map to generate the modifier classes in scss/_buttons.scss.

scss/_buttons.scss

@each $color, $value in $theme-colors {
  .btn-#{$color} {
    @if $color == "light" {
      @include button-variant(
        $value,
        $value,
        $hover-background: shade-color($value, $btn-hover-bg-shade-amount),
        $hover-border: shade-color($value, $btn-hover-border-shade-amount),
        $active-background: shade-color($value, $btn-active-bg-shade-amount),
        $active-border: shade-color($value, $btn-active-border-shade-amount)
      );
    } @else if $color == "dark" {
      @include button-variant(
        $value,
        $value,
        $hover-background: tint-color($value, $btn-hover-bg-tint-amount),
        $hover-border: tint-color($value, $btn-hover-border-tint-amount),
        $active-background: tint-color($value, $btn-active-bg-tint-amount),
        $active-border: tint-color($value, $btn-active-border-tint-amount)
      );
    } @else {
      @include button-variant($value, $value);
    }
  }
}

@each $color, $value in $theme-colors {
  .btn-outline-#{$color} {
    @include button-outline-variant($value);
  }
}