Improvements

[bomsn]

1. This project is in desperate need of a Linter like ESLint. I tried reading the source code on GitHub I couldn't follow it. Spacing inconsistencies is making it hard to follow
2. I would prefer using the hidden boolean attribute instead of accessing the element style and setting it none.
3. Controlling the element visibility isn't enough, you have to disable the element using the disabled boolean attribute to avoid submitting its value. You can use that either on the form input or the fieldset.
4. Your library shouldn't be logging anything to the console. You can use that in debugging if you want but you should either remove it manually or by a script when you ship it. If you want to show an error or a warning using console.warn or throw an error.
5. Using IDs should be prohibited because if the user wants to use your library on more than one instance on the same page, he will have to create elements with the same ID. It's invalid.
6. It's advised to check for the global window object before adding stuff to it. In the case of SSR, the window object isn't available and it would break the build.
   Finally, try to publish it on NPM, it will be a great experience.