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258 lines
11 KiB
Markdown
258 lines
11 KiB
Markdown
---
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layout: docs
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title: Alerts
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description: Provide contextual feedback messages for typical user actions with the handful of available and flexible alert messages.
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group: components
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toc: true
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---
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## Examples
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Alerts are available for any length of text, as well as an optional close button. For proper styling, use one of the eight **required** contextual classes (e.g., `.alert-success`). For inline dismissal, use the [alerts JavaScript plugin](#dismissing).
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{{< example >}}
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{{< alerts.inline >}}
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{{- range (index $.Site.Data "theme-colors") }}
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<div class="alert alert-{{ .name }}" role="alert">
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A simple {{ .name }} alert—check it out!
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</div>{{- end -}}
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{{< /alerts.inline >}}
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{{< /example >}}
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{{< callout info >}}
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{{< partial "callouts/warning-color-assistive-technologies.md" >}}
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{{< /callout >}}
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### Live example
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Click the button below to show an alert (hidden with inline styles to start), then dismiss (and destroy) it with the built-in close button.
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{{< example stackblitz_add_js="true" >}}
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<div id="liveAlertPlaceholder"></div>
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<button type="button" class="btn btn-primary" id="liveAlertBtn">Show live alert</button>
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{{< /example >}}
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We use the following JavaScript to trigger our live alert demo:
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```js
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const alertPlaceholder = document.getElementById('liveAlertPlaceholder')
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const alert = (message, type) => {
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const wrapper = document.createElement('div')
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wrapper.innerHTML = [
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`<div class="alert alert-${type} alert-dismissible" role="alert">`,
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` <div>${message}</div>`,
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' <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>',
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'</div>'
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].join('')
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alertPlaceholder.append(wrapper)
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}
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const alertTrigger = document.getElementById('liveAlertBtn')
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if (alertTrigger) {
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alertTrigger.addEventListener('click', () => {
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alert('Nice, you triggered this alert message!', 'success')
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})
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}
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```
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### Link color
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Use the `.alert-link` utility class to quickly provide matching colored links within any alert.
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{{< example >}}
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{{< alerts.inline >}}
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{{- range (index $.Site.Data "theme-colors") }}
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<div class="alert alert-{{ .name }}" role="alert">
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A simple {{ .name }} alert with <a href="#" class="alert-link">an example link</a>. Give it a click if you like.
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</div>{{ end -}}
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{{< /alerts.inline >}}
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{{< /example >}}
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### Additional content
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Alerts can also contain additional HTML elements like headings, paragraphs and dividers.
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{{< example >}}
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<div class="alert alert-success" role="alert">
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<h4 class="alert-heading">Well done!</h4>
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<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>
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<hr>
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<p class="mb-0">Whenever you need to, be sure to use margin utilities to keep things nice and tidy.</p>
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</div>
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{{< /example >}}
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### Icons
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Similarly, you can use [flexbox utilities]({{< docsref "/utilities/flex" >}}) and [Bootstrap Icons]({{< param icons >}}) to create alerts with icons. Depending on your icons and content, you may want to add more utilities or custom styles.
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{{< example >}}
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<div class="alert alert-primary d-flex align-items-center" role="alert">
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<svg xmlns="http://www.w3.org/2000/svg" class="bi bi-exclamation-triangle-fill flex-shrink-0 me-2" viewBox="0 0 16 16" role="img" aria-label="Warning:">
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<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"/>
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</svg>
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<div>
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An example alert with an icon
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</div>
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</div>
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{{< /example >}}
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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.
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{{< example >}}
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<svg xmlns="http://www.w3.org/2000/svg" style="display: none;">
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<symbol id="check-circle-fill" viewBox="0 0 16 16">
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<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"/>
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</symbol>
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<symbol id="info-fill" viewBox="0 0 16 16">
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<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"/>
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</symbol>
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<symbol id="exclamation-triangle-fill" viewBox="0 0 16 16">
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<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"/>
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</symbol>
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</svg>
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<div class="alert alert-primary d-flex align-items-center" role="alert">
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<svg class="bi flex-shrink-0 me-2" role="img" aria-label="Info:"><use xlink:href="#info-fill"/></svg>
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<div>
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An example alert with an icon
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</div>
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</div>
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<div class="alert alert-success d-flex align-items-center" role="alert">
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<svg class="bi flex-shrink-0 me-2" role="img" aria-label="Success:"><use xlink:href="#check-circle-fill"/></svg>
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<div>
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An example success alert with an icon
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</div>
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</div>
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<div class="alert alert-warning d-flex align-items-center" role="alert">
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<svg class="bi flex-shrink-0 me-2" role="img" aria-label="Warning:"><use xlink:href="#exclamation-triangle-fill"/></svg>
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<div>
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An example warning alert with an icon
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</div>
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</div>
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<div class="alert alert-danger d-flex align-items-center" role="alert">
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<svg class="bi flex-shrink-0 me-2" role="img" aria-label="Danger:"><use xlink:href="#exclamation-triangle-fill"/></svg>
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<div>
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An example danger alert with an icon
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</div>
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</div>
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{{< /example >}}
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### Dismissing
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Using the alert JavaScript plugin, it's possible to dismiss any alert inline. Here's how:
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- Be sure you've loaded the alert plugin, or the compiled Bootstrap JavaScript.
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- Add a [close button]({{< docsref "/components/close-button" >}}) and the `.alert-dismissible` class, which adds extra padding to the right of the alert and positions the close button.
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- On the close button, add the `data-bs-dismiss="alert"` attribute, which triggers the JavaScript functionality. Be sure to use the `<button>` element with it for proper behavior across all devices.
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- To animate alerts when dismissing them, be sure to add the `.fade` and `.show` classes.
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You can see this in action with a live demo:
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{{< example >}}
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<div class="alert alert-warning alert-dismissible fade show" role="alert">
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<strong>Holy guacamole!</strong> You should check in on some of those fields below.
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<button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
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</div>
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{{< /example >}}
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{{< callout warning >}}
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When an alert is dismissed, the element is completely removed from the page structure. If a keyboard user dismisses the alert using the close button, their focus will suddenly be lost and, depending on the browser, reset to the start of the page/document. For this reason, we recommend including additional JavaScript that listens for the `closed.bs.alert` event and programmatically sets `focus()` to the most appropriate location in the page. If you're planning to move focus to a non-interactive element that normally does not receive focus, make sure to add `tabindex="-1"` to the element.
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{{< /callout >}}
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## CSS
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### Variables
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{{< added-in "5.2.0" >}}
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As part of Bootstrap's evolving CSS variables approach, alerts now use local CSS variables on `.alert` for enhanced real-time customization. Values for the CSS variables are set via Sass, so Sass customization is still supported, too.
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{{< scss-docs name="alert-css-vars" file="scss/_alert.scss" >}}
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### Sass variables
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{{< scss-docs name="alert-variables" file="scss/_variables.scss" >}}
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### Sass mixin
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Used in combination with `$theme-colors` to create contextual modifier classes for our alerts.
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{{< scss-docs name="alert-variant-mixin" file="scss/mixins/_alert.scss" >}}
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### Sass loop
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Loop that generates the modifier classes with the `alert-variant()` mixin.
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{{< scss-docs name="alert-modifiers" file="scss/_alert.scss" >}}
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## JavaScript behavior
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### Initialize
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Initialize elements as alerts
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```js
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const alertList = document.querySelectorAll('.alert')
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const alerts = [...alertList].map(element => new bootstrap.Alert(element))
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```
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{{< callout info >}}
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For the sole purpose of dismissing an alert, it isn't necessary to initialize the component manually via the JS API. By making use of `data-bs-dismiss="alert"`, the component will be initialized automatically and properly dismissed.
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See the [triggers](#triggers) section for more details.
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{{< /callout >}}
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### Triggers
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{{% js-dismiss "alert" %}}
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**Note that closing an alert will remove it from the DOM.**
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### Methods
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You can create an alert instance with the alert constructor, for example:
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```js
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const bsAlert = new bootstrap.Alert('#myAlert')
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```
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This makes an alert listen for click events on descendant elements which have the `data-bs-dismiss="alert"` attribute. (Not necessary when using the data-api’s auto-initialization.)
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{{< bs-table >}}
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| Method | Description |
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| --- | --- |
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| `close` | Closes an alert by removing it from the DOM. If the `.fade` and `.show` classes are present on the element, the alert will fade out before it is removed. |
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| `dispose` | Destroys an element's alert. (Removes stored data on the DOM element) |
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| `getInstance` | Static method which allows you to get the alert instance associated to a DOM element. For example: `bootstrap.Alert.getInstance(alert)`. |
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| `getOrCreateInstance` | Static method which returns an alert instance associated to a DOM element or create a new one in case it wasn't initialized. You can use it like this: `bootstrap.Alert.getOrCreateInstance(element)`. |
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{{< /bs-table >}}
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Basic usage:
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```js
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const alert = bootstrap.Alert.getOrCreateInstance('#myAlert')
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alert.close()
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```
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### Events
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Bootstrap's alert plugin exposes a few events for hooking into alert functionality.
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{{< bs-table >}}
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| Event | Description |
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| --- | --- |
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| `close.bs.alert` | Fires immediately when the `close` instance method is called. |
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| `closed.bs.alert` | Fired when the alert has been closed and CSS transitions have completed. |
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{{< /bs-table >}}
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```js
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const myAlert = document.getElementById('myAlert')
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myAlert.addEventListener('closed.bs.alert', event => {
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// do something, for instance, explicitly move focus to the most appropriate element,
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// so it doesn't get lost/reset to the start of the page
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// document.getElementById('...').focus()
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})
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```
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