Javascript dynamic form creation and testing on a server?

I'm not sure if the title is 100% what I'm looking for, but has anyone seen a script or toolkit to allow you to load on a client's server and create forms, fields, give them values and set their end point actions for the purposes of testing? Checking end points, errors, etc all on their server. It doesn't need to be WYSIWYG, just something that works.

Working with a client whose server is locked down, CORS isn't an option, and I'm trying to think of a way to test out our data exchange as much as I can somewhat remotely... and this seemed like a good approach. Writing one myself isn't a worry, but why reinvent the wheel.

Thanks!