Hi
I'm looking to write a some code that can integrate with some of the major online processors. This will be a basic bit of code that depending on a condition will affect the sub-total on check out. I understand that I may have to code it differently for each payment process but is this possible generally speaking?
I want to provide the code so that users can integrate it into their checkout process, I guess as some sort of plug-in/widget.
Any suggestions greatly appreciated.