PHP 相关知识

1，正则匹配中文字符：/^[\x{4e00}-\x{9fa5}]+$/u

   eg: preg_match("/^[\x{4e00}-\x{9fa5}]+$/u", $string);

2，PHP获取用户访问真实IP地址

function getIP ()

{

    global $_SERVER;

     if (getenv('HTTP_CLIENT_IP')) {

        $ip = getenv('HTTP_CLIENT_IP');

    } else if (getenv('HTTP_X_FORWARDED_FOR')) {

        $ip = getenv('HTTP_X_FORWARDED_FOR');

    } else if (getenv('REMOTE_ADDR')) {

        $ip = getenv('REMOTE_ADDR');

    } else {

        $ip = $_SERVER['REMOTE_ADDR'];

    }

    return $ip;

}