XML takes over the user interface
I recently wrote about 'Why XML is taking over the world'. The latest part of the world to be taken over is forms processing. The W3C made XForms a full recommendation on October 14th.
XForms is an XML standard for defining and implementing forms. A form is a user interface for inputting information. A simple example would be a request for tickets for a theatre. The form will enable the input of the following information: the date, which program, number of tickets and type of tickets. Related to the information are a set of business rules such as the date must be a valid date on which the theatre is open, the program must be matinee or evening, ... Finally the rendering of the form will be different depending on the device (browser, voice recognition …), the language (Welsh, English…) or the accessibility requirements.
Forms have been developed for browsers using HTML. These have been difficult to implement and change because they did not separate out the message, from the rules and the rendering. XForms has built on other XML standards such as XML schemas, XPath, CSS and XHTML to create a clear separation.
The standard has been nearly four years in development and the committee has included most of the industry leaders including IBM, Microsoft, Nokia, Oracle and Novell. The committee has also included some small companies, and it is the small companies who have developed the first working examples of the standard. X-Smiles, a part of Helsinki University, have developed a web browser that includes support for XForms; x-port.net, a small UK firm, have developed an XForms processor that runs inside Microsoft's IE6. Two implementations were needed before W3C would ratify the standard as a full recommendation.
These two implementations have put the XForms processor in the browser. This means that the XML messages and the XForms definition are sent to the browser were a suitable plug-in processor can render the form and process the business rules without returning to the server. This is a very elegant and powerful solution but does require a copy of the processor to be installed. The first production uses of these products have been in intranet solutions where the distribution of the new code is not a problem. Using this technique on the internet has really only just become viable with the W3C ratification. x-port.net provides copies of their processor to be downloaded for free direct from their site, thereby making XForms on the browser just as possible as Acrobat on the browser.
Other software companies, such as Hyfinity, have already started to use the standard but only as a definitional tool. In these cases they take the XForms definitions on the server and transform it into, and out of, XHTML and Java script that runs on the browser. They get considerable development productivity by using a standards based approach and by the clear separation of messages, rules and rendering. This approach avoids the need for downloads of a processor, this may be attractive in some environments. It is obviously possible to mix and match the two approaches as they both use the same definitions.
The ability to mix match emphasises the power of XForms as it shows how a single definition can be used to drive different implementations.
XForms has created a great deal of interest in industries that have a large number of forms, with a larger number of users, across different languages and platforms. The biggest interest has been in e-government, finance and internal applications such as HR. But in reality all sectors and types of companies have a requirement for simplified forms processing, and faster more productive development. Now that XForms is a standard we can see it rapidly impacting forms processing but also impacting application development.
Copyright 2003. Originally published by IT-Director.com, reprinted with permission. IT-Director.com provides IT decision makers with free daily e-mails containing news analysis, member-only discussion forums, free research, technology spotlights and free on-line consultancy. To register for a free e-mail subscription, click here.
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