yii\web\View::renderHeadHtml PHP Method

    protected function renderHeadHtml()
    {
        $lines = [];
        if (!empty($this->metaTags)) {
            $lines[] = implode("\n", $this->metaTags);
        }
        if (!empty($this->linkTags)) {
            $lines[] = implode("\n", $this->linkTags);
        }
        if (!empty($this->cssFiles)) {
            $lines[] = implode("\n", $this->cssFiles);
        }
        if (!empty($this->css)) {
            $lines[] = implode("\n", $this->css);
        }
        if (!empty($this->jsFiles[self::POS_HEAD])) {
            $lines[] = implode("\n", $this->jsFiles[self::POS_HEAD]);
        }
        if (!empty($this->js[self::POS_HEAD])) {
            $lines[] = Html::script(implode("\n", $this->js[self::POS_HEAD]), ['type' => 'text/javascript']);
        }
        return empty($lines) ? '' : implode("\n", $lines);
    }