XForms: the classical form, in a new way

Forms are a part of our lives. They are used day by day in the ordinary life, but online they have a special place. They are the primary way of collecting information, being used for search engines, polls, surveys, electronic commerce, and even on-line applications. Every type of user-interaction on-line is done through web-forms of some sort. However, this technology is already showing it’s age. Being created 5 years before XML, it has limitations, that make developer’s and user’s lives harder. Among them are:

• As forms are older than XML, the integration between them is very poor
• Every common tasks made on form’s information requires a great amount of scripting
• Forms run well only on desktop browsers, depending on the device it is being run on
• They have great limits in accessibility
• They are hard to learn, because of the blending of purpose and presentation.

A new W3C standard, the XForms, come to substitute the old forms, in order to add some additional features and ease the work for the developers. The goals that XForms tend to accomplish are:

• Improvement on XML and XML Schema integration
• Simplification of common-related tasks, so that less scripting would be required
• Device-independence, so that it could work on all types of computers
• Universal Accessibility
• Separation of purpose from presentation.

XForms is an XML technology, that is very close to XSLT processing. They both use the instance data that is based on XML and defined in terms of XPath’s internal tree representation. Of course, there are some differences between them. XSLT is usually defined in terms of three trees, resultant from parsing XML documents. But XForms combines the input and output trees, so often in the diagrams you would see it as the representation of only two trees, resulted from parsing XML documents. The flow of data in XForms is in the following way:

1. The information that comes either inline, or from an XML document is parsed into memory.
2. The information from the instance data is being processed. That involved the interaction with the user and recording of the received data.
3. The submitted data is processed, being transformed usually into XML, and sent to the server