jQuery used to be virtually indispensable, if you wanted to develop a cross-browser website without getting a headache.
Today, however, you might not need jQuery, especially, if you’re developing a library and want to avoid unnecessary dependencies.
Still, some helpers could be useful... Vanillin is an opinionated set of helpers that I find most useful, a bare minimum to make life easier.
Forms are complicated. There are many things you must take into consideration: binding an existing object (if any) to each sparate field of the form, validating them after user has submited the form, if invalid redisplaying it with POST data bound and with validation errors, binding the data back to an object...
Avris Forms add an abstraction layer that handles all of that. You just need to define the list of fields you need and their cofiguration options. You’ll get an object that will handle everything for you. Just handle it in the controller and display it in the view.