Class yii\jui\DatePicker

                public function init()
{
    parent::init();
    if ($this->inline && !isset($this->containerOptions['id'])) {
        $this->containerOptions['id'] = $this->options['id'] . '-container';
    }
    if ($this->dateFormat === null) {
        $this->dateFormat = Yii::$app->formatter->dateFormat;
    }
}

            

                protected function renderWidget()
{
    $contents = [];
    // get formatted date value
    if ($this->hasModel()) {
        $value = Html::getAttributeValue($this->model, $this->attribute);
    } else {
        $value = $this->value;
    }
    if ($value !== null && $value !== '') {
        // format value according to dateFormat
        try {
            $value = Yii::$app->formatter->asDate($value, $this->dateFormat);
        } catch(InvalidParamException $e) {
            // ignore exception and keep original value if it is not a valid date
        }
    }
    $options = $this->options;
    $options['value'] = $value;
    if ($this->inline === false) {
        // render a text input
        if ($this->hasModel()) {
            $contents[] = Html::activeTextInput($this->model, $this->attribute, $options);
        } else {
            $contents[] = Html::textInput($this->name, $value, $options);
        }
    } else {
        // render an inline date picker with hidden input
        if ($this->hasModel()) {
            $contents[] = Html::activeHiddenInput($this->model, $this->attribute, $options);
        } else {
            $contents[] = Html::hiddenInput($this->name, $value, $options);
        }
        $this->clientOptions['defaultDate'] = $value;
        $this->clientOptions['altField'] = '#' . $this->options['id'];
        $contents[] = Html::tag('div', null, $this->containerOptions);
    }
    return implode("\n", $contents);
}

            

                public function run()
{
    echo $this->renderWidget() . "\n";
    $containerID = $this->inline ? $this->containerOptions['id'] : $this->options['id'];
    $language = $this->language ? $this->language : Yii::$app->language;
    if (strncmp($this->dateFormat, 'php:', 4) === 0) {
        $this->clientOptions['dateFormat'] = FormatConverter::convertDatePhpToJui(substr($this->dateFormat, 4));
    } else {
        $this->clientOptions['dateFormat'] = FormatConverter::convertDateIcuToJui($this->dateFormat, 'date', $language);
    }
    if ($language !== 'en-US') {
        $view = $this->getView();
        $assetBundle = DatePickerLanguageAsset::register($view);
        $assetBundle->language = $language;
        $options = Json::htmlEncode($this->clientOptions);
        $language = Html::encode($language);
        $view->registerJs("jQuery('#{$containerID}').datepicker($.extend({}, $.datepicker.regional['{$language}'], $options));");
    } else {
        $this->registerClientOptions('datepicker', $containerID);
    }
    $this->registerClientEvents('datepicker', $containerID);
    JuiAsset::register($this->getView());
}