I'm new to php. Is it possible to add code within the description textbox in the cheque gateway? I tried but the code becomes visible in the checkout page (except <?PHP which is not visible).
Background: I am using the cheque gateway for a cash-before-delivery option. The service provider for this option only operates in certain cities. They have provided me with a CSV file of Post Codes they can service. I need to check if the customer, when choosing this payment option, has provided a valid post code. One option I thought of would be a text input field within the payment gateway option where the customer can enter the post code and a button next to it "check if available". Once the customer clicks, it checks the CSV if the pin code is serviceable and displays a dialog box with success or failure message.