Usable, accessible, device-independent forms deployment with XForms

Steven Pemberton

W3C and CWI, Amsterdam, The Netherlands

CWI
Kruislaan 413
P.O. Box 94079
1090 GB Amsterdam
The Netherlands

Email: Steven.Pemberton@cwi.nl

Tel: +31 624 671 668

http://www.cwi.nl/~steven/

Abstract

HTML Forms, introduced in 1993, were the basis of the e-commerce revolution and have become the mainstay for interaction and data submission on the web. After 10 years experience however it has become clear how to improve on them, for the end user, the author, and the owners of the services that the forms are addressing. XForms is the new technology replacing HTML Forms.

The advantages of XForms include:

• It improves the user experience: XForms has been designed to allow much to be checked by the browser, such as types of fields being filled in, or that one date is later than another. This reduces the need for round trips to the server or for extensive script-based solutions, and improves the user experience by giving immediate feedback to what is being filled in.
• It is XML, and it can submit XML.
• It combines existing XML technologies: Rather than reinventing the wheel, XForms uses a number of existing XML technologies, such as XPath for addressing and calculating values, and XML Schemas for defining data types. This has a dual benefit: ease of learning for people who already know these technologies, and implementors can use off-the-shelf components to build their systems.
• It is internationalized.
• It is accessible: XForms has been designed so that it will work equally well with accessible technologies (for instance for blind users) and with traditional visual browsers
• It is device independent: The same form can be delivered without change to a traditional browser, a PDA, a mobile phone, a voice browser, and even some more exotic emerging clients such as instant messengers. This greatly eases providing forms to a wide audience, since forms only need to be authored once.
• It is easier to author complicated forms.

The approach taken is to separate data, functionality, controls and presentation. The data collected is essentially an XML document, which can be anything from a single data value, right up to a complete document, even XHTML. The data can be internal to the form, or in an external document loaded separately. Functionality includes assigning types and other properties to values, and describing declarative relationships between them. Data can be submitted in traditional 'legacy' form, or posted as XML; communication with web services is therefore simple. The form controls are intent-based, describing their purpose rather than how they look or how they should be implemented. This aids device independence since rather than saying you want radio buttons, you say that one value should be chosen from a list of values. The device can then choose a suitable representation. The controls additionally support use cases like data with repeating elements, and wizard-style approaches. Finally style sheets are used to describe representations for particular devices or modalities.

This talk will discuss the design aims of XForms and the approach taken for usability, accessibility and device independence, and demonstrate some new use cases.

The Speaker

Steven Pemberton is a researcher at the CWI, Amsterdam, the Dutch national research institute for mathematics and computer science. He has been involved with the Web from the beginning, organising two workshops at the first WWW conference in 1994, and chairing the first Style Sheets Workshop in 1995. He is chair of the HTML and Forms Working Groups at the World Wide Web Consortium W3C, and co-author of amongst others HTML, CSS, XHTML and XForms. He was until recently editor-in-chief of ACM/interactions.