Detailed code comments , make ease for further developments.
Integrate with actual usage scenes, to present a individually-designed style for every single payment method.
Highly customisable, everthing on the page can be changed through pre-configured JavaScript variables. No need for any programming technique, while being easy to use.
In-depth user experience considerations; by thinking thoughtfully and having the passion to always keep UX as the first priority, you and your users' experiences when configuring / using merger could only be described as 'shift'.
The use of public CDN on static files (where applicable) will speed-up the loading.