Integrating our Products: XForms

Steven Pemberton, CWI, Amsterdam and W3C
Chair, W3C HTML and Forms Working Groups

XForms: integration

XForms integrates a large number of W3C Products:

• XML
• Namespaces
• Schemas
• CSS
• XPath
• XML Events
• XML Base
• XHTML Modularisation
• Web services (soon)

XForms: Outegration

And XForms is designed to be integrated into other products (it is not a host language in itself):

• XHTML2
• SVG
• SMIL
• ...

The Structure of XForms

XForms have two orthogonal parts:

• The Model
• The User Interface

The Model

The Model contains a number of things:

• instance(s)

  Data that is being used, manipulated, and/or submitted by the Form

  May be in the XForms document, or external.

  Any XML document

• Schemas

  Data types can be checked on the client; better usability, less trips to the server.

The Model (more)

• Bindings, constraints, calculations on and between instance data

  Values can be calculated without resorting to scripting

• Details of how to submit

  Submission is as an XML document (plus legacy formats)

The User Interface

The User Interface binds into data in an instance.

• Uses XPath to bind
• Means there is no need for 'hidden' UI controls

The XForms set of UI controls are abstract controls, representing the intent of the control, not its look. You can then use CSS etc., for generating a presentation.

This means (amongst other things) that you can generate different presentations for different devices from the same form.

Control Example

For instance a select1 represents the notion of selecting a single value from a list. It can then be rendered as

• Radio buttons
• Select list
• Drop down/pop up menu
• (or anything else you can come up with)

You can even use different presentations for different devices.

Any XML Document

Demo

Hurdles

In integrating products, we have met a few hurdles:

• Composing XML documents together (think xml:id)
• Entities
• Media types for mixed-namespace documents

Demonstrations

XForms is now in CR, coming close to PR.

Last week we had an implementation workshop. There are at least 20 implementations that we know of, as well as 2 that only implement the model.

David Landwehr is from Novell. They have a Java-based XForms implementation, and he will be demonstrating some basic XForms functionality.

Mikko Honkala is from Helsinki University of Technology, and he will be demonstrating his X-Smiles browser, which not only implements XForms, but integrates loads of different W3C (and other) technologies (SMIL, SVG, XHTML, CSS, XFrames, ...). He will be demonstrating XForms integrated with just a few of these.