Issue link: https://read.uberflip.com/i/1146286
Web 2.0, DHTML, and Ajax | 97 Web 2.0 O'Reilly Media first used the term "Web 2.0" in 2004, the first year they held the Web 2.0 conference. The term pertains not as much to technology as the social and business aspects of how the next-generation Internet will be used. It alludes to web sites evolving into Internet communities rich in wikis, blogs, and podcasts. Key con- cepts of Web 2.0 include a rich, application-like user interface and the aggregation of information from multiple web services. In effect, the web page becomes more and more like an application with well-defined inputs and outputs. DHTML and Ajax are technologies for implementing these concepts. In his web article "Web 2.0 Compact Definition: Trying Again" (http://radar.oreilly.com/archives/2006/12/web_20_compact. html), Tim O'Reilly provides one of the most referenced definitions of Web 2.0. DHTML Dynamic HTML allows the presentation of an HTML page to change after the page has loaded. This is accomplished using JavaScript and CSS interacting with the Doc- ument Object Model (DOM) in the browser. Examples include links that change when the user hovers the mouse over them, tree controls that expand and collapse, and cascading menus within the page. More complex DHTML pages may redraw the entire page based on the user's intention; for example, changing from viewing an email inbox to a form for composing an email message. Ajax is a technology used in DHTML so that the client can retrieve and display new information requested by the user without reloading the page. Ajax The term "Ajax" was coined in 2005 by Jesse James Garrett. * Ajax stands for "Asyn- chronous JavaScript and XML" (although today there are alternatives to XML, most notably JSON). Ajax is not a single, licensable technology, but is instead a collection of technologies, primarily JavaScript, CSS, DOM, and asynchronous data retrieval. The goal of Ajax is to break out of the start-and-stop nature of interaction on the Web. Displaying a blank white screen to the user followed by repainting the entire window is not a good user experience. Instead, Ajax inserts a layer between the UI and web server. This Ajax layer resides on the client, interacting with the web server to get requested information, and interfacing with the presentation layer to update only the components necessary. It transforms the Web experience from "viewing pages" to "interacting with an application." * Jesse James Garrett, "Ajax: A New Approach to Web Applications," http://www.adaptivepath.com/ publications/essays/archives/000385.php.