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Alerts

Provide contextual feedback messages for typical user actions with the handful of available and flexible alert messages.

On this page

Examples

Alerts are available for any length of text, as well as an optional close button. For proper styling, use one of the four required contextual classes (e.g., .alert-success). For inline dismissal, use the alerts JavaScript plugin.

<div class="alert alert-success" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Success</span></span>
  <p>Success notification text goes here.</p>
</div>
<div class="alert alert-info" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Info</span></span>
  <p>Information notification text goes here.</p>
</div>
<div class="alert alert-warning" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Warning</span></span>
  <p>Warning notification text goes here.</p>
</div>
<div class="alert alert-danger" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Error</span></span>
  <p>Error notification text goes here.</p>
</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.

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.

<div id="liveAlertPlaceholder"></div>
<button type="button" class="btn btn-primary" id="liveAlertBtn">Show live alert</button>

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

var alertPlaceholder = document.getElementById('liveAlertPlaceholder')
var alertTrigger = document.getElementById('liveAlertBtn')

function alert(message, type, typeVisuallyHidden) {
  var wrapper = document.createElement('div')
  wrapper.innerHTML = '<div class="alert alert-' + type + ' alert-dismissible" role="alert"><span class="alert-icon"><span class="visually-hidden">' + typeVisuallyHidden + '</span></span><p>' + message + '</p><button type="button" class="btn-close" data-bs-dismiss="alert"><span class="visually-hidden">Close</span></button></div>'

  alertPlaceholder.append(wrapper)
}

if (alertTrigger) {
  alertTrigger.addEventListener('click', function () {
    alert('Nice, you triggered this alert message!', 'success', 'Success')
  })
}

Sizes

Alerts come with a smaller variant: .alert-sm.

<div class="alert alert-success alert-sm" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Success</span></span>
  <p>Success notification text goes here.</p>
</div>
<div class="alert alert-info alert-sm" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Info</span></span>
  <p>Information notification text goes here.</p>
</div>
<div class="alert alert-warning alert-sm" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Warning</span></span>
  <p>Warning notification text goes here.</p>
</div>
<div class="alert alert-danger alert-sm" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Error</span></span>
  <p>Error notification text goes here.</p>
</div>

Additional content

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

<div class="alert alert-success" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Success</span></span>
  <div>
    <h4 class="alert-heading">Success notification text goes here.</h4>
    <p>Description text goes here.</p>
  </div>
</div>

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 Boosted JavaScript.
  • Add a 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:

<div class="alert alert-warning alert-dismissible fade show" role="alert">
  <span class="alert-icon"><span class="visually-hidden">Warning</span></span>
  <p>Warning notification text goes here.</p>
  <button type="button" class="btn-close" data-bs-dismiss="alert"><span class="visually-hidden">Close</span></button>
</div>
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.

Sass

Variables

$alert-padding-y:                   1rem;
$alert-padding-x:                   $spacer;
$alert-margin-bottom:               $spacer;
$alert-border-radius:               $border-radius;
$alert-link-font-weight:            null;
$alert-border-width:                $border-width;

// Boosted mod
$alert-padding-sm:                  $spacer * .5;
$alert-colors:                      map-remove($theme-colors, "primary", "secondary", "light", "dark");
$alert-icons: (
  "success": var(--#{$boosted-variable-prefix}success-icon),
  "info":    escape-svg($info-icon),
  "warning": escape-svg($warning-icon),
  "danger":  var(--#{$boosted-variable-prefix}error-icon)
);
$alert-logo-size:                   add($spacer * .5, 1rem);
$alert-logo-size-sm:                add(1rem, 1px);
$alert-icon-size:                   3rem;
$alert-icon-margin-y:               $spacer * .1;
$alert-btn-close-offset:            .5rem;
$alert-btn-close-offset-sm:         $spacer * .25;
// End mod

$alert-dismissible-padding-r:       $alert-padding-y * 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 $color, $value in $alert-colors {
  .alert-#{$color} {
    border-color: $value;

    .alert-icon::before {
      background-image: map-get($alert-icons, $color);
    }
  }
}

JavaScript behavior

Initialize

Initialize elements as alerts

var alertList = document.querySelectorAll('.alert')
var alerts =  [].slice.call(alertList).map(function (element) {
  return new boosted.Alert(element)
})

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.

Triggers

Dismissal can be achieved with the data attribute on a button within the alert as demonstrated below:

<button type="button" class="btn-close" data-bs-dismiss="alert"><span class="visually-hidden">Close</span></button>

or on a button outside the alert using the data-bs-target as demonstrated below:

<button type="button" class="btn-close" data-bs-dismiss="alert" data-bs-target="#my-alert"><span class="visually-hidden">Close</span></button>

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

Methods

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, you can use it like this: boosted.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: boosted.Alert.getOrCreateInstance(element) 
var alertNode = document.querySelector('.alert')
var alert = boosted.Alert.getInstance(alertNode)
alert.close()

Events

Boosted’s alert plugin exposes a few events for hooking into alert functionality.

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. 
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()
})