This is pretty much it, but I guess form submissions and POST data would come under the same topic.Creating a login/register script is relatively easy. In order to do this, research and understand how to use the following topics:
- Sessions
- SQL Databases
- MySQLi/PDO
- PHP Form Submissions
- POST Data
- if/else functions
These are the basics to creating a login & register script, but be aware that there are other things that I didn't mention, like securing post data, hashing passwords, etc.