What you describe has two parts: creating a form and filling it in (presumably with storing the results somewhere). While the second part is relatively simple,

What you describe has two parts: creating a form and filling it in (presumably with storing the results somewhere). While the second part is relatively simple, the first one requires quite some work. And although you can do it in vanilla JS, you'll be better of using some libraries. It also depends what you mean by "creating" a form. If you can just choose from a predefined set of templates, it would make things much easier, and you could get away without using a JS framework (or even without JS at all, if you wish - you can use a more traditional approach with RoR, Django etc). But my general impression is that people drastically underestimate the amount of work that needs to be done in order to make a complete app, with authorization, user roles, properly secured etc.