kartik\tree\TreeViewInput::registerInputAssets PHP Method

    public function registerInputAssets()
    {
        if (!$this->asDropdown) {
            return;
        }
        $view = $this->getView();
        TreeViewInputAsset::register($view);
        $id = $this->options['id'];
        $name = 'treeinput';
        $opts = Json::encode(['treeId' => $this->treeOptions['id'], 'inputId' => $this->dropdownConfig['input']['id'], 'dropdownId' => $this->dropdownConfig['dropdown']['id'], 'placeholder' => $this->_placeholder, 'value' => empty($this->value) ? '' : $this->value, 'caret' => $this->dropdownConfig['caret'], 'autoCloseOnSelect' => $this->autoCloseOnSelect]);
        $var = $name . '_' . hash('crc32', $opts);
        $this->options['data-krajee-' . $name] = $var;
        $view->registerJs("var {$var}={$opts};", View::POS_HEAD);
        $view->registerJs("jQuery('#{$id}').{$name}({$var});");
    }