彻底解决跨浏览器下PHP下载文件名中的中文乱码问题

        
    $ua = $_SERVER["HTTP_USER_AGENT"];
    
    $filename = "中文 文件名.txt";
    $encoded_filename = urlencode($filename);
    $encoded_filename = str_replace("+", "%20", $encoded_filename);
    
    header('Content-Type: application/octet-stream');
    
    if (preg_match("/MSIE/", $ua)) {
        header('Content-Disposition: attachment; filename="' . $encoded_filename . '"');
    } else if (preg_match("/Firefox/", $ua)) {
        header('Content-Disposition: attachment; filename*="utf8\'\'' . $filename . '"');
    } else {
        header('Content-Disposition: attachment; filename="' . $filename . '"');
    }

    ?>