limited email signup

A small request from me to the community, some of them might have the same issues when lots of email signups are emails from domains you have never known before.

those signups are mostly 99% spam accounts that have been passed through your firewalls, even if you set up a whole wall of defense against this. They will always find their way.

To prevent this, i hardly coded a small script that can be used for development purposes and i hope also as a future update.

this should be placed in the functions.php of your theme file. However, some code is self-made while other parts of the code are fetches on the web. its also not tested yet but i hope that this is a good contribution for an even better arcane. ( code comes after this post )