How to write correctly about. communication in pure JS?

Question

htaccess

Issue closed or resolved.
Thanks to everyone who tried to help.

Answer 1

I didn’t really understand the essence of the question, what is the difficulty?)
Do you mean form windows as different forms? or a form in several steps?
For the first case:
In popular plugins like fancybox, ajax, modals work on the content of the date href tag.
And nothing prevents you from writing a form generator on the back and, depending on the get parameter, collecting the form you need.
For the second one, you need to think, it will most likely be an array of urls for generating steps.