XForms is an XML format for the specification of a data processing model for XML data and user interface(s) for the XML data, such as web forms. XForms was designed to be the next generation of HTML / XHTML forms, but is generic enough that it can also be used in a standalone manner or with presentation languages other than XHTML to describe a user interface and a set of common data manipulation tasks.
XForms 1.0 (Third Edition) was published on 29 October 2007. The original XForms specification became an official W3C Recommendation on 14 October 2003, while XForms 1.1, which introduced a number of improvements, reached the same status on 20 October 2009.
Read more about XForms: Differences From HTML Forms, Software Support, Implementation Technologies Compared, XRX Application Architecture