how to Link php login form to another website

Question

I have a login form in PHP and MySQL for example in a domain named "login.example.com" and I want it to login to another website for example "home.example.com" at the same time that I login into the first domain, how can I do it without using cookies?

The values that I want to transfer between the domains is the email and the password.

$email       =  e($_POST['email']);                                                            //The email of the user
$password  =  e($_POST['password']);                                                       //The password of the user

Answer 1

You have two options,

1. After login approved, redirect to the second domain (subdomain) and set the session there too

2. After login approved, load a pixel image with the URL of your second domain (subdomain) EX :

   echo "< img href=' https://sub.example.com ' />"

In both option, you have to run the script on your second domain (subdomain) to set the session

Update

Example to set a session :

$_SESSION['login'] = $id;

Update 2

It's not a good practice to transfer email and password between domains (subdomains), it's not secure, but you can setting cookie or session to identify the email and password with a unique ID which could be transferred between domains (subdomains)