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警報 (Alerts)

使用少量可用及彈性的警報訊息為使用者操作提供上下文的內容回饋。

On this page

範例

警報適用於任何長度的文本，以及可選的關閉按鈕。為了呈現正確的樣式，請必需使用 8 個內文樣式類別中的其中一個（例如 .alert-success）。對於行內的移除，請使用 alerts JavaScript plugin。

A simple primary alert—check it out!

A simple secondary alert—check it out!

A simple success alert—check it out!

A simple danger alert—check it out!

A simple warning alert—check it out!

A simple info alert—check it out!

A simple light alert—check it out!

A simple dark alert—check it out!

<div class="alert alert-primary" role="alert">
  A simple primary alert—check it out!
</div>
<div class="alert alert-secondary" role="alert">
  A simple secondary alert—check it out!
</div>
<div class="alert alert-success" role="alert">
  A simple success alert—check it out!
</div>
<div class="alert alert-danger" role="alert">
  A simple danger alert—check it out!
</div>
<div class="alert alert-warning" role="alert">
  A simple warning alert—check it out!
</div>
<div class="alert alert-info" role="alert">
  A simple info alert—check it out!
</div>
<div class="alert alert-light" role="alert">
  A simple light alert—check it out!
</div>
<div class="alert alert-dark" role="alert">
  A simple dark alert—check it out!
</div>

Conveying meaning to assistive technologies

Using color to add meaning only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (e.g. the visible text), or is included through alternative means, such as additional text hidden with the .visually-hidden class.

連結顏色

使用 .alert-link 通用類別快速為警報中的連結增添合適的色彩。

A simple primary alert with an example link. Give it a click if you like.

A simple secondary alert with an example link. Give it a click if you like.

A simple success alert with an example link. Give it a click if you like.

A simple danger alert with an example link. Give it a click if you like.

A simple warning alert with an example link. Give it a click if you like.

A simple info alert with an example link. Give it a click if you like.

A simple light alert with an example link. Give it a click if you like.

A simple dark alert with an example link. Give it a click if you like.

<div class="alert alert-primary" role="alert">
  A simple primary alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>
<div class="alert alert-secondary" role="alert">
  A simple secondary alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>
<div class="alert alert-success" role="alert">
  A simple success alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>
<div class="alert alert-danger" role="alert">
  A simple danger alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>
<div class="alert alert-warning" role="alert">
  A simple warning alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>
<div class="alert alert-info" role="alert">
  A simple info alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>
<div class="alert alert-light" role="alert">
  A simple light alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>
<div class="alert alert-dark" role="alert">
  A simple dark alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
</div>

額外的內容

警報還可以包含其他的 HTML 元素，像是標題、段落以及分隔線。

Well done!

Aww yeah, you successfully read this important alert message. This example text is going to run a bit longer so that you can see how spacing within an alert works with this kind of content.

Whenever you need to, be sure to use margin utilities to keep things nice and tidy.

<div class="alert alert-success" role="alert">
  <h4 class="alert-heading">Well done!</h4>
  <p>Aww yeah, you successfully read this important alert message. This example text is going to run a bit longer so that you can see how spacing within an alert works with this kind of content.</p>
  <hr>
  <p class="mb-0">Whenever you need to, be sure to use margin utilities to keep things nice and tidy.</p>
</div>

Icons

Similarly, you can use flexbox utilities and Bootstrap Icons to create alerts with icons. Depending on your icons and content, you may want to add more utilities or custom styles.

An example alert with an icon

<div class="alert alert-primary d-flex align-items-center" role="alert">
  <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" fill="currentColor" class="bi bi-exclamation-triangle-fill flex-shrink-0 me-2" viewBox="0 0 16 16" role="img" aria-label="Warning:">
    <path d="M8.982 1.566a1.13 1.13 0 0 0-1.96 0L.165 13.233c-.457.778.091 1.767.98 1.767h13.713c.889 0 1.438-.99.98-1.767L8.982 1.566zM8 5c.535 0 .954.462.9.995l-.35 3.507a.552.552 0 0 1-1.1 0L7.1 5.995A.905.905 0 0 1 8 5zm.002 6a1 1 0 1 1 0 2 1 1 0 0 1 0-2z"/>
  </svg>
  <div>
    An example alert with an icon
  </div>
</div>

Need more than one icon for your alerts? Consider using more Bootstrap Icons and making a local SVG sprite like so to easily reference the same icons repeatedly.

An example alert with an icon

An example success alert with an icon

An example warning alert with an icon

An example danger alert with an icon

<svg xmlns="http://www.w3.org/2000/svg" style="display: none;">
  <symbol id="check-circle-fill" fill="currentColor" viewBox="0 0 16 16">
    <path d="M16 8A8 8 0 1 1 0 8a8 8 0 0 1 16 0zm-3.97-3.03a.75.75 0 0 0-1.08.022L7.477 9.417 5.384 7.323a.75.75 0 0 0-1.06 1.06L6.97 11.03a.75.75 0 0 0 1.079-.02l3.992-4.99a.75.75 0 0 0-.01-1.05z"/>
  </symbol>
  <symbol id="info-fill" fill="currentColor" viewBox="0 0 16 16">
    <path d="M8 16A8 8 0 1 0 8 0a8 8 0 0 0 0 16zm.93-9.412-1 4.705c-.07.34.029.533.304.533.194 0 .487-.07.686-.246l-.088.416c-.287.346-.92.598-1.465.598-.703 0-1.002-.422-.808-1.319l.738-3.468c.064-.293.006-.399-.287-.47l-.451-.081.082-.381 2.29-.287zM8 5.5a1 1 0 1 1 0-2 1 1 0 0 1 0 2z"/>
  </symbol>
  <symbol id="exclamation-triangle-fill" fill="currentColor" viewBox="0 0 16 16">
    <path d="M8.982 1.566a1.13 1.13 0 0 0-1.96 0L.165 13.233c-.457.778.091 1.767.98 1.767h13.713c.889 0 1.438-.99.98-1.767L8.982 1.566zM8 5c.535 0 .954.462.9.995l-.35 3.507a.552.552 0 0 1-1.1 0L7.1 5.995A.905.905 0 0 1 8 5zm.002 6a1 1 0 1 1 0 2 1 1 0 0 1 0-2z"/>
  </symbol>
</svg>

<div class="alert alert-primary d-flex align-items-center" role="alert">
  <svg class="bi flex-shrink-0 me-2" width="24" height="24" role="img" aria-label="Info:"><use xlink:href="#info-fill"/></svg>
  <div>
    An example alert with an icon
  </div>
</div>
<div class="alert alert-success d-flex align-items-center" role="alert">
  <svg class="bi flex-shrink-0 me-2" width="24" height="24" role="img" aria-label="Success:"><use xlink:href="#check-circle-fill"/></svg>
  <div>
    An example success alert with an icon
  </div>
</div>
<div class="alert alert-warning d-flex align-items-center" role="alert">
  <svg class="bi flex-shrink-0 me-2" width="24" height="24" role="img" aria-label="Warning:"><use xlink:href="#exclamation-triangle-fill"/></svg>
  <div>
    An example warning alert with an icon
  </div>
</div>
<div class="alert alert-danger d-flex align-items-center" role="alert">
  <svg class="bi flex-shrink-0 me-2" width="24" height="24" role="img" aria-label="Danger:"><use xlink:href="#exclamation-triangle-fill"/></svg>
  <div>
    An example danger alert with an icon
  </div>
</div>

移除

使用警報的 JavaScript 插件，他能夠將行內的警報移除，使用如下：

請確認你有載入警報插件，或者是編譯後的 Bootstrap JavaScript。
加上一個關閉按鈕並賦予 .alert-dismissible 類別，使警報的右上角新增額外的 padding 和關閉按鈕。
在關閉按鈕加上 data-bs-dismiss="alert" 屬性來觸發 JavaScript 函式。務必使用 <button> 元素，讓它可以跨裝置正常運行。
要以動態方式移除警報，可以使用 .fade 和 .show 類別。

你可以參考下方的動態範例：

Holy guacamole! You should check in on some of those fields below.

<div class="alert alert-warning alert-dismissible fade show" role="alert">
  <strong>Holy guacamole!</strong> You should check in on some of those fields below.
  <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
</div>

當警報被移除時，元素就會完全地從頁面中移除。如果是操作鍵盤的用戶使用關閉按鈕消除了警報，他們會突然失去焦點，需根據瀏覽器重新整理此頁面/文件。因此，建議使用其他 JavaScript 讓他可以監聽 closed.bs.alert 事件並以編程方式設定 focus()在頁面中最合適的位置。如果您打算將 focus 轉成非交互式元素，請確保將其添加 tabindex="-1" 到該元素。

Sass

Variables

$alert-padding-y:               $spacer;
$alert-padding-x:               $spacer;
$alert-margin-bottom:           1rem;
$alert-border-radius:           $border-radius;
$alert-link-font-weight:        $font-weight-bold;
$alert-border-width:            $border-width;
$alert-bg-scale:                -80%;
$alert-border-scale:            -70%;
$alert-color-scale:             40%;
$alert-dismissible-padding-r:   $alert-padding-x * 3; // 3x covers width of x plus default padding on either side

Variant mixin

Used in combination with $theme-colors to create contextual modifier classes for our alerts.

@mixin alert-variant($background, $border, $color) {
  color: $color;
  @include gradient-bg($background);
  border-color: $border;

  .alert-link {
    color: shade-color($color, 20%);
  }
}

Loop

Loop that generates the modifier classes with the alert-variant() mixin.

// Generate contextual modifier classes for colorizing the alert.

@each $state, $value in $theme-colors {
  $alert-background: shift-color($value, $alert-bg-scale);
  $alert-border: shift-color($value, $alert-border-scale);
  $alert-color: shift-color($value, $alert-color-scale);
  @if (contrast-ratio($alert-background, $alert-color) < $min-contrast-ratio) {
    $alert-color: mix($value, color-contrast($alert-background), abs($alert-color-scale));
  }
  .alert-#{$state} {
    @include alert-variant($alert-background, $alert-border, $alert-color);
  }
}

JavaScript 行為

觸發

透過 JavaScript 來移除警報：

var alertList = document.querySelectorAll('.alert')
alertList.forEach(function (alert) {
  new bootstrap.Alert(alert)
})

或者使用警報中的按鈕 data 屬性，如上所示：

<button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>

請注意，關閉警報會將其從 DOM 中刪除。

方法

你可以使用警報的結構建立一個警報實例，例如：

var myAlert = document.getElementById('myAlert')
var bsAlert = new bootstrap.Alert(myAlert)

這使警報監聽具有 data-bs-dismiss="alert" 屬性的後代元素中的點擊事件。（當使用 data-api 的 auto-initialization 可以不需要。）

Method	Description
`close`	從 DOM 中刪除來關閉警報。如果元素上出現 `.fade` and `.show` 類別, 則警報會在刪除之前淡出。
`dispose`	銷毀一個元素的警報 (移除 DOM 元素上儲存的資料)
`getInstance`	一個可以讓你取得與 DOM 元素關聯之警報實例的靜態方法，你可以這樣使用: `bootstrap.Alert.getInstance(alert)`

var alertNode = document.querySelector('.alert')
var alert = bootstrap.Alert.getInstance(alertNode)
alert.close()

事件

Bootstrap 警報插件提供額外的事件，可以直接取用警報函式。

Event	Description
`close.bs.alert`	當調用 `close` 實例方法時，此事件會立即觸發。
`closed.bs.alert`	警報關閉時，會觸發此事件（等待CSS轉換完成）。

var myAlert = document.getElementById('myAlert')
myAlert.addEventListener('closed.bs.alert', function () {
  // do something, for instance, explicitly move focus to the most appropriate element,
  // so it doesn't get lost/reset to the start of the page
  // document.getElementById('...').focus()
})