@xabbuh Thanks for opening this. We need to keep track of what we do and don't have, and where. for example:

• The submit() instead of bind() is covered already in cookbook/form/direct_submit.rst, but not directly in the form component
• The method and action are covered in the form book chapter, but not (until this PR) in the component
• The form_start and form_end are covered in the form book chapter, but not in the components
• Using a button is mentioned in the form chapter, but we don't really talk about configuration, except for its reference documentation.

It's difficult because the form component has a significant amount of duplication, in part because we thought that we might try to make it work for both the component and framework all in one page (but I don't think that makes sense anymore). Ideally, I'd like to find a way to duplicate less.

Let me know what you think!

@weaverryan I absolutely agree with you when talking about duplicated documentation. My suggestion is, to first complete the documentation with this pull request (so that all the things you mentioned have been covered) and afterwards discuss how to deal with duplicated documentation separately (I opened #4100 to for this). What do you think?

Yep, let's do that. You already have #4100 opened to track the duplication, so we can finish this PR, which will make sure that everything is covered and accomplished. 👍

Alright, I think I can manage to complete this til the end of the week.

When it comes to duplicated documentation, we have to talk about form_start() and form_end() again. Looking at how it is done yet, I'm not sure if it really makes sense to document it twice. In the components documentation we already have a paragraph like this in the rendering section:

That’s it! By printing form_widget(form), each field in the form is rendered, along with a label and error message (if there is one). As easy as this is, it’s not very flexible (yet). Usually, you’ll want to render each form field individually so you can control how the form looks. You’ll learn how to do that in the “Rendering a Form in a Template” section.

“Rendering a Form in a Template” directly links to the appropriate section in the book chapter.

For submit() I decided to not duplicate any documentation, but to link to the cookbook article from the book and from the component instead.

I think the features you can use with buttons are already documented in the book:

• Submitting Forms with Multiple Buttons
• validation based on the clicked button

What do you think? Should we duplicate or move parts of this to the component section?

@xabbuh I agree with you! So, I think this PR is ready, except for one small comment I just left.

Thanks!

@weaverryan I added a small note on it.

Very-nicely written note. cheers Christian!