Using a Javascript Function in a Wix Business Application

When you use any of those applications in wix you get a ready-made user interface for the full application. velo and write basically a javascript function that would implement a certain API. All of those are constitute into our business API starting from a simple CRM solution to a global payment solution. The code a velo code runs both on the front end and on the back end now in the front end i guess it's kind of easy to to understand  it's a development model that's kind of similar to working with the dome.