Hello Incomedia, Guru, Expert

Into the custom payement windows we can use HTML/JS . OK fine... (just syntax is not pure HTML coding with no tag !!!! it's a website syntax NOT DOCUMENTED ...)

But how to call a PHP file.... Many payment gateways  (not to say ALL ...) are based on PHP coding ...

Nothing found into documentation on how to use PHP into custom form for the payment ?

This one below does not works !!!

Thanks for your precious feedback

https://wsx5.afsoftware.fr