public function script($callbackName = null)
    {
        $script = '';

        if ( ! $this->scriptLoaded) {
            $script = '<script src="' . $this->getScriptSrc($callbackName) . '" async defer></script>';
            $this->scriptLoaded = true;
        }

        return $script;
    }
public function script($callbackName = null)
    {
        $script = '';

        if ( ! $this->scriptLoaded) {
            $script = '<script src="' . $this->getScriptSrc($callbackName) . '" async defer></script>';
            $this->scriptLoaded = true;
        }

        return $script;
    }
public function script ( $ callbackName = null ) { $ script = '' ; if ( ! $ this -> scriptLoaded ) { $ script = '<script src="' . $ this -> getScriptSrc ( $ callbackName ) . '" async defer></script>' ; $ this -> scriptLoaded = true ; } return $ script ; }
Get script tag.

@param  string|null  $callbackName

@return string
Get script tag .