Chapter 1. XML Powered Web Forms

Since their inception in 1993, HTML forms have come to form the underpinnings of user interaction on the World Wide Web (WWW). The convenience afforded by the ability to deploy applications at all levels of complexity on the Web, and thereby provide consistent end- user access to information and application services via a universal Web client, created a platform-independent environment for electronic commerce across the Internet.

However, building on the essential simplicity of HTML forms has resulted in an extremely complex Web programming model; today, Web application developers are forced to work at different levels of abstraction ”and, consequently, duplicate application and business logic in multiple programming languages ”in order to deliver a satisfactory end-user experience. These problems become even more complex given the need to perform electronic transactions with a variety of different devices and user interface modalities. As we deploy Web access to software at all levels of complexity ranging from business back-ends to simple electronic transactions, these issues can be better addressed by revisiting the design of HTML forms that are the essential underpinnings of the transactional Web.

XForms ”a revision to the existing HTML forms technology developed by the World Wide Web Consortium (W3C) ^[1] ”builds on the advantages of XML to create a versatile forms module that can stand the Web in good stead for the next decade .

^[1] http://www.w3.org

Section 1.1 traces the evolution of Web applications and describes the problems inherent in the present-day Web programming model that motivated the work on XForms. We design a simple questionnaire application using HTML forms in Section 1.2 and enumerate the software components needed to deploy the questionnaire on the Web. We then recast this application in XForms in Section 1.3 to give a bird's-eye view of the various components that constitute W3C XForms. We conclude this chapter with a summary of key XForms features and their benefits in Section 1.4. The remaining chapters of this book will cover these components in detail along with numerous examples that illustrate their use.