php富文本保留120汉字

    if($data['content']){
        $intro = strip_tags($data['content']);//去除html标签
        $pattern = '/s/';//去除空白
        $intro = preg_replace($pattern, '', $intro);
        $data['desc'] = mb_substr($intro, 0, 120,"UTF-8");//截取120个汉字
    }