XForms

XForms is an XML format used for collecting inputs from 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.

In contrast to the original web forms (originally defined in HTML), the creators of XForms have used a model–view–controller (MVC) approach. The model consists of one or more XForms models describing form data, constraints upon that data, and submissions. The view describes what controls appear in the form, how they are grouped together, and what data they are bound to. CSS can be used to describe a form's appearance.

An XForms document can be as simple as a web form (by only specifying the submission element in the model section, and placing the controls in the body), but XForms includes many advanced features. For example, new data can be requested and used to update the form while it is running, much like using XMLHttpRequest/AJAX except without scripting. The form author can validate user data against XML Schema data types, require certain data, disable input controls or change sections of the form depending on circumstances, enforce particular relationships between data, input variable length arrays of data, output calculated values derived from form data, prefill entries using an XML document, respond to actions in real time (versus at submission time), and modify the style of each control depending on the device they are displayed on (browser versus mobile versus text only, etc.). There is often no need for any scripting with languages such as JavaScript. However, XForms does include an event model and actions for implementing more complex form behaviors. Actions and event handling are specified using the XForms XML dialect rather than more common scripting languages like JavaScript.

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