protected function _renderSrc($url, array $attrs = array()) {
        if ('http://' !== substr($url, 0, 7)
            && 'https://' !== substr($url, 0, 8)
            && '//' !== substr($url, 0, 2)
        ) {
            $url = $this->view->assetUrl($url);
        }
        $attrs['src'] = $url;
        $attrs = $this->_htmlAttribs($attrs);
        return "<script{$attrs}></script>";
    }