Abstract
An important aspect of Web 2.0, mentioned by Tim O’Reilly, is the rich user experience. Web 2.0 applications offer the user a desktop-like interface to bring back efficiency and productivity. The click-wait-andrefresh- cycle of normal Web applications leads to a less responsive, and thus less efficient, user interface. To serve the needs of these so-called rich Internet applications (RIA), many different approaches have emerged, based either on Web standards or on proprietary approaches. This chapter aims at defining a qualified criterion system for comparing RIA platforms. Thereafter, those RIA platforms are selected and analyzed in terms of the criterion system that is most likely to become widely accepted.
TopDefinitions
Web application A Web application is an application “accessed over the World Wide Web by using a Web browser” (“WHATWG FAQ”).
Rich Internet Application (RIA) The term was coined by Macromedia in 2002. “Macromedia defines RIAs as combining the best user interface functionality of desktop software applications with the broad reach and low-cost deployment of Web applications and the best of interactive, multimedia communication. The end result: an application providing a more intuitive, responsive, and effective user experience. Specifically, the best of the desktop includes providing an interactive user interface for validation and formatting, fast interface response times with no page refresh, common user interface behaviors such as drag-and-drop and the ability to work online and offline. The best of the Web includes capabilities such as instant deployment, cross-platform availability, the use of progressive download for retrieving content and data, the magazine-like layout of Web pages and leveraging widely adopted Internet standards. The best of communication means incorporating two-way interactive audio and video” (Duhl, 2003).
Asynchronous JavaScript + XML (AJAX) “Ajax isn’t a technology. It’s really several technologies, each flourishing in its own right, coming together in powerful new ways. Ajax incorporates:
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standards-based presentation using XHTML and CSS;
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dynamic display and interaction using the Document Object Model;
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data interchange and manipulation using XML and XSLT;
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asynchronous data retrieval using XMLHttpRequest;
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and JavaScript binding everything together” (Garret, 2005).
Offline Web applicationOffline Web Applications utilize Web technologies to build desktop applications. To enable the applications to run online and offline, they have to be granted file access in order to be able to save states (“TR10: Offline Web Applications”).
RIA runtime environment An RIA runtime environment provides an environment that allows running platform independent RIAs. Usually, the runtime environment is available for different operating systems.
RIA framework The term RIA framework is used in this text to describe an application framework that supports the development of RIAs for one or more RIA runtime environments.
Key Terms in this Chapter
Rich Internet Application: Applications called RIAs provide a more intuitive, responsive, and effective user experience. This is done by utilizing user interface components and behaviors know from desktop applications.
All-Audience Applications: Applications potentially targeting every Internet user. Thus, this type of application has to take care that each potential user can access and use the application, regardless of which browser is installed on his system. If browser plug-ins are needed, only plug-ins with a very high market penetration are sufficient.
Rich User Experience: The experience of a user using traditional Web applications and websites is characterized by the Click-Wait-and-Refresh-Cycle and the available set of user interface components. Thus, a rich experience is built up by adding additional interface components and behaviors and the Click-Wait-and-Refresh-Cycle is avoided by retrieving and presenting data from the server without refreshing the whole page.
Web Application: A Web application is an application accessed over the WWW using a Web browser. It is built on Web standards. Additionally, proprietary Web technologies may be used.
AJAX: AJAX stands for Asynchronous JavaScript + XML. It is not one technology, but a combination of technologies. These include HTML, Cascading Stylesheets (CSS), Document Object Model (DOM), XML, Extensible Stylesheet Language Transformations (XSLT), XMLHttpRequest, and JavaScript. HTML and CSS are used for presentation. DOM allows manipulation of the presentation and interaction. XML and XSLT are used for data interchange and manipulation. XMLHttpRequest allows retrieval of data. JavaScript is used to define the underlying logic and interaction of the other technologies.
Click-Wait-and-Refresh-Cycle: This term was coined by Kevin Hakman (2006) . It describes the way users interact with traditional Web applications. A user clicks on a button or link, and the request is sent to the server and processed. The user waits until the results are returned to the Web browser, which refreshes the presentation.