code: public static function getInputId($model, $attribute)
      {
          $charset = Yii::$app ? Yii::$app->charset : 'UTF-8';
          $name = mb_strtolower(static::getInputName($model, $attribute), $charset);
          return str_replace(['[]', '][', '[', ']', ' ', '.'], ['', '-', '-', '', '-', '-'], $name);
      }
docs: Generates an appropriate input ID for the specified attribute name or expression.
  
  This method converts the result [[getInputName()]] into a valid input ID.
  For example, if [[getInputName()]] returns `Post[content]`, this method will return `post-content`.
  @param Model $model the model object
  @param string $attribute the attribute name or expression. See [[getAttributeName()]] for explanation of attribute expression.
  @return string the generated input ID
  @throws InvalidArgumentException if the attribute name contains non-word characters.