How to get local IP address?

Question

PHP

Hey!
How to get the local IP address of a mobile device in PHP.
There is a Wi-Fi router that distributes the Internet to mobile devices (mobile phones / laptops).
How to get exactly the local IP address of the client assigned by the router . I write like this: but the script gives out the IP address through which I go to the Internet. Tried many ways but nothing works. But, after all, how do they get my local address on 2ip.ua?
echo $_SERVER['REMOTE_ADDR'];

Answer 1

They recognize it in js code, not in php.

Answer 2

echo $_SERVER['SERVER_ADDR'];