Merge pull request yiisoft#12747 from werew01f/master

afterInit event for yiiActiveForm

framework/CHANGELOG.md

@@ -83,6 +83,7 @@ Yii Framework 2 Change Log
 - Enh #12440: Added `yii\base\Event::offAll()` method allowing clear all registered class-level event handlers (klimov-paul)
 - Enh #12580: Make `yii.js` comply with strict and non-strict javascript mode to allow concatenation with external code (mikehaertl)
 - Enh #12664: Added support for wildcards for `optional` at `yii\filters\auth\AuthMethod` (mg-code)
+- Enh #12744: Added `afterInit` event to `yii.activeForm.js` (werew01f)
 - Enh: Method `yii\console\controllers\AssetController::getAssetManager()` automatically enables `yii\web\AssetManager::forceCopy` in case it is not explicitly specified (pana1990, klimov-paul)
 - Enh #12198: Added `time` and `datetime` validator short names (nkovacs)
 

framework/assets/yii.activeForm.js

@@ -100,7 +100,15 @@
          *  - jqXHR: a jqXHR object
          *  - textStatus: the status of the request ("success", "notmodified", "error", "timeout", "abort", or "parsererror").
          */
-        ajaxComplete: 'ajaxComplete'
+        ajaxComplete: 'ajaxComplete',
+        /**
+         * afterInit event is triggered after yii activeForm init.
+         * The signature of the event handler should be:
+         *     function (event)
+         * where
+         *  - event: an Event object.
+         */        
+        afterInit: 'afterInit'
     };
 
     // NOTE: If you change any of these defaults, make sure you update yii\widgets\ActiveForm::getClientOptions() as well
@@ -217,6 +225,8 @@
                     });
                     $form.on('submit.yiiActiveForm', methods.submitForm);
                 }
+                var event = $.Event(events.afterInit);
+                $form.trigger(event);
             });
         },