Author: Alexander Kochetov (creocoder@gmail.com)
Inheritance: extends yii\web\AssetBundle
 /**
  * Registers required script for the plugin to work as jQuery File Uploader
  */
 public function registerClientScript()
 {
     $view = $this->getView();
     if ($this->plus) {
         FileUploadPlusAsset::register($view);
     } else {
         FileUploadAsset::register($view);
     }
     $options = Json::encode($this->clientOptions);
     $id = $this->options['id'];
     $js[] = ";jQuery('#{$id}').fileupload({$options});";
     if (!empty($this->clientEvents)) {
         foreach ($this->clientEvents as $event => $handler) {
             $js[] = "jQuery('#{$id}').on('{$event}', {$handler});";
         }
     }
     $view->registerJs(implode("\n", $js));
 }