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This widget offers an easy method to embed a Bootstrap alert on your page with various configurable options. The widget extends the \yii\bootstrap\Alert class with additional features and enhancements:

  • Alert Types: Easily set an alert style through the type property. Adds two new types other than the 4 standard bootstrap alert types.
  • Icon & Title Section: Ability to set a stylish title separator section and add an icon and title for each alert as a header.
  • Fade: Ability to set a fade duration to automatically fade out the alerts after display.


This widget can be also installed in isolation outside this bundle if needed. In addition to using via \kartik\widgets namespace, this widget can be also installed from the yii2-widget-alert repository and can also be accessed via \kartik\alert\Alert namespace.


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Alert supports configuration of the bootstrap library version so that you can use this either with any Bootstrap version 3.x and above. For setting up the bootstrap version for your extension, you can configure the Alert::bsVersion property to one of the following.

  • To use with bootstrap 3 library - you can set Alert::bsVersion property to any string starting with 3 (e.g. 3 or 3.3.7 or 3.x)

  • To use with bootstrap 4 library - you can set Alert::bsVersion property to any string starting with 4 (e.g. 4 or 4.6.0 or 4.x)

  • To use with bootstrap 5 library - you can set Alert::bsVersion property to any string starting with 5 (e.g. 5 or 5.1.0 or 5.x)

The following sections describe the pre-requisites for enabling Bootstrap library specific version support in your application and other related controls/overrides.

Global Bootstrap Version

Generally, you may also want to set a default version globally for all Krajee Extensions (instead of setting it for each widget or extension separately). In order to do this, you can setup the bsVersion property within Yii 2 application params (i.e. Yii::$app->params['bsVersion']). To set this up, add this section of code to your application params configuration file (e.g. config/params.php):

'params' => [
    'bsVersion' => '5.x', // this will set globally `bsVersion` to Bootstrap 5.x for all Krajee Extensions
    // other settings
    // 'adminEmail' => ''

If Alert::bsVersion property is set, in addition to Yii::$app->params['bsVersion'], the extension level setting (Alert::bsVersion property) will override the Yii::$app->params['bsVersion']. If Alert::bsVersion property is not set, and Yii::$app->params['bsVersion'] is also not set, Alert::bsVersion property will default to 3.x (i.e. Bootstrap 3.x version will be assumed as default).

Yii2 Bootstrap Dependency

You need to install one of yiisoft/yii2-bootstrap or yiisoft/yii2-bootstrap4 or yiisoft/yii2-bootstrap5 extensions manually in your application to enable Bootstrap 3.x or 4.x or 5.x functionality respectively. This dependency has not been pre-built into the composer configuration for Krajee extensions, to allow better control to the developers in configuring their bootstrap library version. If bsVersion is set to 5.x and yiisoft/yii2-bootstrap5 is not installed, then an exception message will be thrown mentioning you to install the yiisoft/yii2-bootstrap5 extension. If bsVersion is set to 4.x and yiisoft/yii2-bootstrap4 is not installed, then an exception message will be thrown mentioning you to install the yiisoft/yii2-bootstrap4 extension. Similarly, if bsVersion is set to 3.x and yiisoft/yii2-bootstrap is not installed, an exception message will be thrown mentioning you to install the yiisoft/yii2-bootstrap extension.

To install yiisoft/yii2-bootstrap5, add the repo to the require section of your application's composer.json.

"yiisoft/yii2-bootstrap5": "@dev"

To install yiisoft/yii2-bootstrap4, add the repo to the require section of your application's composer.json.

"yiisoft/yii2-bootstrap4": "@dev"

To install yiisoft/yii2-bootstrap, add the repo to the require section of your application's composer.json.

"yiisoft/yii2-bootstrap": "@dev"

Override Bootstrap CSS/JS

The Krajee extension asset bundle(s) by default depend on one of the following asset bundles to load the Bootstrap CSS and JS:

  • yii\bootstrap\BootstrapAsset and/or yii\bootstrap\BootstrapPluginAsset for bootstrap 3.x (bsVersion = 3 setting)

  • yii\bootstrap4\BootstrapAsset and/or yii\bootstrap4\BootstrapPluginAsset for bootstrap 4.x ( bsVersion = 4 setting)

  • yii\bootstrap5\BootstrapAsset and/or yii\bootstrap5\BootstrapPluginAsset for bootstrap 5.x (bsVersion = 5 setting)

This is controlled by the property bsDependencyEnabled within the asset bundle (which defaults to true). One can override this and prevent the default yii2 bootstrap assets (CSS & JS) from loading by doing one or all of the following:

  • Global Override: Set Yii::$app->params['bsDependencyEnabled'] to false in your Yii 2 application config params.php. This setting will be applied for all Krajee Extension Asset Bundles that depend on Bootstrap assets.

    'params' => [
        'bsDependencyEnabled' => false, // this will not load Bootstrap CSS and JS for all Krajee extensions
        // you need to ensure you load the Bootstrap CSS/JS manually in your view layout before Krajee CSS/JS assets
        // other params settings below
        // 'bsVersion' => '5.x',
        // 'adminEmail' => ''
  • Asset Bundle Specific Override: Set bsDependencyEnabled to false for the specific asset bundle within Yii2 Asset Manager component in your Yii 2 application config file.

    // ...
    'components' => [
        'assetManager' => [
            'bundles' => [
                'kartik\form\ActiveFormAsset' => [
                    'bsDependencyEnabled' => false // do not load bootstrap assets for a specific asset bundle


When setting bsDependencyEnabled to false, you need to ensure that your app code/view layout loads the Bootstrap CSS and JS on your view before the Krajee CSS/JS are loaded to ensure that the Krajee extension JS plugins and CSS styles do not get broken.

Icons for Bootstrap

Bootstrap 5.x / 4.x does not include glyphicons or any other icons framework bundled with the library. Krajee extensions therefore will use Font Awesome 5.x icons instead of glyphicons when working with Bootstrap 5.x / 4.x. You can download Font Awesome 5.x icons from the icons website. Alternatively, you can load the free version of Font Awesome from their CDN.

For Krajee extensions and demos, the Font Awesome Free version is used and loaded as the Icons Display Package on all the Yii2 demo layouts. To include font awesome assets on your page, include the following markup on the HEAD section of your view layout file, when bsVersion is set to 4.x or 5.x.

  • Option 1: Font CSS version of Font Awesome:

    <!-- on your view layout file HEAD section -->
    <link rel="stylesheet" href="">
  • Option 2: SVG / JS version of Font Awesome (recommended for cleaner scaling vector icons and features like icon layers):

    <!-- on your view layout file HEAD section -->
    <script defer src="" crossorigin="anonymous"></script>

    Alternatively, you can use the FontAwesomeAsset from the kartik-v/yii2-icons package to load the SVG/JS version.

    // on your view layout file
    use kartik\icons\FontAwesomeAsset;

The yii2-widget-alert extension can be installed automatically or manually using one of these options:

Composer Package Manager Recommended

Installation via Composer is the recommended and most easy option to install Krajee Yii2 extensions. You can install yii2-widget-alert via composer package manager. Either run:

$ php composer.phar require kartik-v/yii2-widget-alert "dev-master"

or add:

"kartik-v/yii2-widget-alert": "dev-master"

to your application's composer.json file.

Manual Install

You may also manually install the extension to your project (in case your composer install does not work). Just download the source ZIP or TAR ball and extract the extension asset files and folders into your project. You may need to install dependencies manually and also set the namespaces to the extensions in your Yii2 extensions configurations manually.

Alert Demo (Configure)

use kartik\widgets\Alert;

echo Alert::widget([
    'type' => Alert::TYPE_SUCCESS,
    'title' => 'Well done!',
    'icon' => 'fas fa-check-circle',
    'body' => 'You successfully read this important alert message.',
    'showSeparator' => true,
    'delay' => 2000
echo Alert::widget([
    'type' => Alert::TYPE_INFO,
    'title' => 'Heads up!',
    'icon' => 'fas fa-info-circle',
    'body' => 'This alert needs your attention, but it\'s not super important.',
    'showSeparator' => true,
    'delay' => 4000
echo Alert::widget([
    'type' => Alert::TYPE_WARNING,
    'title' => 'Warning!',
    'icon' => 'fas fa-exclamation-circle',
    'body' => 'Better check yourself, you\'re not looking too good.',
    'showSeparator' => true,
    'delay' => 6000
echo Alert::widget([
    'type' => Alert::TYPE_DANGER,
    'title' => 'Oh snap!',
    'icon' => 'fas fa-times-circle',
    'body' => 'Change a few things up and try submitting again.',
    'showSeparator' => true,
    'delay' => 8000
The widget supports all parameters that one would pass for the Yii Bootstrap Alert Widget. The additional parameter settings specially available for this widget are:
  • type: string the type of the alert widget. Defaults to 'alert-info' or Alert::TYPE_INFO. You can select one of the following options:

    • Alert::TYPE_INFO: Sets it to 'alert-info' CSS class.

    • Alert::TYPE_DANGER: Sets it to 'alert-danger' CSS class.

    • Alert::TYPE_SUCCESS: Sets it to 'alert-success' CSS class.

    • Alert::TYPE_WARNING: Sets it to 'alert-warning' CSS class.

    • Alert::TYPE_PRIMARY: Sets it to 'bg-primary' CSS class.

    • Alert::TYPE_DEFAULT: Sets it to 'well' CSS class.

    • Alert::TYPE_CUSTOM: Use this for setting no style and adding your own custom style. You can pass in any style/class settings to the options to style your alert.

  • iconType: string the icon type - can be 'class' (the CSS class) or 'image' (the image url). Defaults to 'class'.

  • icon: string the class name for the icon to be displayed in the title section. If you want to display an image - you can set an image source here and set the iconType property to image.

  • iconOptions: array the HTML attributes for the icon.

  • title: string display a title for the alert (this is not HTML encoded). This will help display a title with a message separator and an optional bootstrap icon. If this is null or not set, it will not be displayed.

  • titleOptions: array the HTML attributes for the title. Defaults to ['class' => 'kv-alert-title']. The following options are additionally recognized:

    • tag: string the tag to display the title. Defaults to 'span'.

  • showSeparator: boolean whether to show the title separator. Only applicable if title is set.

  • body: string the alert message body.

  • delay: integer|boolean time in milliseconds after which each alert fades out. If set to 0 or false, alerts will never fade out and will be displayed forever.

  • options: array the HTML attributes for the alert container.


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visitors to Krajee Yii2 Demos since 22-May-2017