We have a domain ( form.com ) where we *do* have an authorization form.
We want the user to be automagically authorized on another domain ( check.com )
once he/she has been authorized on form.com
2.1. Place auth_form.php somewhere on form.com
(in this example it is supposed to be in form.com/auth_form.php).
2.2. Place auth_check.php somewhere on check.com.
(in this example it is supposed to be in check.com/auth_check.php).
2.3. That's it! Now, once the user has been authorized on form.com/auth_form.php,
he/she becomes automagically authorized on check.com
*** NOTE *** :
of course, you'll have to implement your own login/password verification mechanism,
as well as userID/passwordHash approving function - instead of dummy "fake_approval"
used in auth_check.php