使用$ _SERVER ['PHP_SELF']的Php表单值

I'm struggling trying to create a form in php and get the values with a $_POST, sounds easy but my problem is the "path" of the php file.

Example : Index.php -> include text.php -> include form.php

When I click "submit" in the form I cannot get anything because the web goes to "self" which is not form.php, it's index.php !!

Anyone knows how to submit a form a do nothing? just store the field values in $_POST['name'], for instance.

Maybe if I put an "isset" in index.php and another one in text.php ? have to be something easier.

Can I get the $_POST in ajax for instance ?

Thanks in advanced.