PHP获取公网ip

function getpublicip()
{
    if (!empty($_SERVER["HTTP_CLIENT_IP"])) {

        $cip = $_SERVER["HTTP_CLIENT_IP"];
    } elseif (!empty($_SERVER["HTTP_X_FORWARDED_FOR"])) {

        $cip = $_SERVER["HTTP_X_FORWARDED_FOR"];
    } elseif (!empty($_SERVER["REMOTE_ADDR"])) {

        $cip = $_SERVER["REMOTE_ADDR"];
    } else {

        $cip = "无法获取！";
    }
    print "您的IP地址是：" . $cip;
}