This is about a payment module which exists for magento (up to version 1.9) and needs to be upgraded for magento version 2/2.1.
You can see a demo of the working version at [login to view URL] and the source code is here: [login to view URL]
As you can see there is actually no form in this module, just a remote javascript call which opens an iframe modal (same functionality as braintree button).
Respond if you think you are up for the task.