public static function btn($href, $content, $attr = ['class' => 'btn btn-default'], $params = array('tag' => 'a', 'attrHref' => 'href'))
    {
        $params = Arr::mergeWithDefaultParams($params);

        if(preg_match('/^fa-/', $content)){
            $content = "<i class=\"fa ".$content.'"></i>';
        } elseif(preg_match('/^glyphicon-/', $content)){
            $content = "<i class=\"glyphicon ".$content.'"></i>';
        }

        return '<'.$params['tag'].' '.$params['attrHref'].'="'.$href.'" '. Html::attributes($attr) .'>'.$content.'</'.$params['tag'].'>';
    }