Web Forms 2.0: Editor & Libraries

I would like to build a web application where users can create forms with very few technical knowledge. Since they need "advanced" features like validations, required fields and some more, I am currently evaluating XForms and web forms 2.0 (from HTML 5 spec). Concerning web forms, my research couldn't find any answers for the following questions:

1. Are there any (JavaScript) libraries out there which make web forms fully available in browsers which have currently no support for them (i.e. 开发者_StackOverflow中文版Firefox)?
2. Is there a "web forms editor" which allows creating input and select fields, with setting attributes like the type, required, ...? It has to be something visual, and must create "nice" html.

Any help/ hints would be appreciated!

I thought I'd register to post a message about this, as I've been looking into this as well in the last few weeks.

WebForms2 on Google Code tries to implement most web form features, but it hasn't been updated in a while. http://code.google.com/p/webforms2/

About editors, I don't think there are any. The HTML5 Forms spec hasn't been finalised, and browsers barely support it right now. There doesn't seem to be any consensus about how the inputs will be styled just yet either.

And I can't seem to post more than 1 link per message just yet. So see message above for the other link ;-)

There is some information about HTML5 Forms support on Anne van Kesteren's blog posted 10 days ago. http://annevankesteren.nl/2010/04/html5-forms

Cheers!