0
0
mirror of https://github.com/twbs/bootstrap.git synced 2024-12-14 02:24:00 +01:00
Bootstrap/site/content/docs/5.3/components/alerts.md
2023-05-31 19:28:32 -07:00

10 KiB
Raw Blame History

layout title description group toc
docs Alerts Provide contextual feedback messages for typical user actions with the handful of available and flexible alert messages. components true

Examples

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.

{{< callout info >}} Heads up! As of v5.3.0, the alert-variant() Sass mixin is deprecated. Alert variants now have their CSS variables overridden in a Sass loop. {{< /callout >}}

{{< example >}} {{< alerts.inline >}} {{- range (index $.Site.Data "theme-colors") }}

A simple {{ .name }} alert—check it out!
{{- end -}} {{< /alerts.inline >}} {{< /example >}}

{{< callout info >}} {{< partial "callouts/warning-color-assistive-technologies.md" >}} {{< /callout >}}

Live example

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.

{{< example stackblitz_add_js="true" >}}

Show live alert {{< /example >}}

We use the following JavaScript to trigger our live alert demo:

{{< js-docs name="live-alert" file="site/assets/js/snippets.js" >}}

Use the .alert-link utility class to quickly provide matching colored links within any alert.

{{< example >}} {{< alerts.inline >}} {{- range (index $.Site.Data "theme-colors") }}

A simple {{ .name }} alert with an example link. Give it a click if you like.
{{ end -}} {{< /alerts.inline >}} {{< /example >}}

Additional content

Alerts can also contain additional HTML elements like headings, paragraphs and dividers.

{{< example >}}

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.

{{< /example >}}

Icons

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.

{{< example >}}

An example alert with an icon
{{< /example >}}

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.

{{< example >}}

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
{{< /example >}}

Dismissing

Using the alert JavaScript plugin, it's possible to dismiss any alert inline. Here's how:

  • Be sure you've loaded the alert plugin, or the compiled Bootstrap JavaScript.
  • 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.
  • 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.
  • To animate alerts when dismissing them, be sure to add the .fade and .show classes.

You can see this in action with a live demo:

{{< example >}}

Holy guacamole! You should check in on some of those fields below.
{{< /example >}}

{{< callout warning >}} 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. {{< /callout >}}

CSS

Variables

{{< added-in "5.2.0" >}}

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.

{{< scss-docs name="alert-css-vars" file="scss/_alert.scss" >}}

Sass variables

{{< scss-docs name="alert-variables" file="scss/_variables.scss" >}}

Sass mixins

{{< deprecated-in "5.3.0" >}}

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

{{< scss-docs name="alert-variant-mixin" file="scss/mixins/_alert.scss" >}}

Sass loops

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

{{< scss-docs name="alert-modifiers" file="scss/_alert.scss" >}}

JavaScript behavior

Initialize

Initialize elements as alerts

const alertList = document.querySelectorAll('.alert')
const alerts = [...alertList].map(element => new bootstrap.Alert(element))

{{< callout info >}} 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.

See the triggers section for more details. {{< /callout >}}

Triggers

{{% js-dismiss "alert" %}}

Note that closing an alert will remove it from the DOM.

Methods

You can create an alert instance with the alert constructor, for example:

const bsAlert = new bootstrap.Alert('#myAlert')

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-apis auto-initialization.)

{{< bs-table >}}

Method Description
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.
dispose Destroys an element's alert. (Removes stored data on the DOM element)
getInstance Static method which allows you to get the alert instance associated to a DOM element. For example: bootstrap.Alert.getInstance(alert).
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).
{{< /bs-table >}}

Basic usage:

const alert = bootstrap.Alert.getOrCreateInstance('#myAlert')
alert.close()

Events

Bootstrap's alert plugin exposes a few events for hooking into alert functionality.

{{< bs-table >}}

Event Description
close.bs.alert Fires immediately when the close instance method is called.
closed.bs.alert Fired when the alert has been closed and CSS transitions have completed.
{{< /bs-table >}}
const myAlert = document.getElementById('myAlert')
myAlert.addEventListener('closed.bs.alert', event => {
  // 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()
})