adaptive path blog about us services events publications products contact home home publications essays essay for february 18, 2005 Ajax: A New Approach to Web Applications Publications sections: Essay archives Newsletter Reading list Recent Essays Sarah Nelson Interviews scott berkun at mx san francisco February 22, 2007 Nine Adaptive pathers share their Resolutions for 2007 January 4, 2007 Interview with Tim Brown, ceo of ideo January 3, 2007 Tagging vs Cataloging: What It's All About November 30, 2006 Organizing Your Global Corporate Intranet November 10, 2006 Essay Archives》 by Jesse James Garrett February 18, 2005 If anything about current interaction design can be called "glamorous, it's creating Web applications. After all, when was the last time you heard someone
blog | about us | services | events | publications | products | contact | home | home > publications > essays > essay for february 18, 2005 Ajax: A New Approach to Web Applications Publications Sections: • Reports • Latest essay • Essay archives • Newsletter • Reading list Recent Essays • Sarah Nelson Interviews Scott Berkun at MX San Francisco February 22, 2007 • Nine Adaptive Pathers Share Their Resolutions for 2007 January 4, 2007 • Interview with Tim Brown, CEO of IDEO January 3, 2007 • Tagging vs. Cataloging: What It's All About November 30, 2006 • Organizing Your Global Corporate Intranet November 10, 2006 Essay Archives » by Jesse James Garrett February 18, 2005 If anything about current interaction design can be called “glamorous,” it’s creating Web applications. Af ter all, when was the last time you heard someone
rave about the interaction design of a product that wasnt on the Web?(okay besides the ipod. ) All the cool, innovative new projects are online Despite this, Web interaction designers cant help but feel a little env io us of our collea gues who create desktop software. Desktop applications have a richness and responsiveness that has seemed out of reach on the Web. The same simp licity that enabled the Web's rapid proliferation also creates a gap between the experiences we can provide and the experiences users can get from a desktop application That gap is closing. Take a look at Google Suggest. Watch the way the suggested terms update as you type almost instantly. Now look at Google Maps. Zoom in. Use your cursor to grab the map and scroll around a bit Aga in, everything happens almost instantly, with no waiting for pages to reload Google Suggest and google maps are two examples of a new approach to web applications that we at Adaptive Path have been calling ajax. the name is shorthand for Asynchronous Java Script XML, and it represents a fundamental ible on the web Defining Ajax Ajax isn't a tec ly several technologie ch flourishing in own right, coming together in powerful new ways. Ajax incorporates standards-based presentation using XHTML and CSs dynamic display and interaction using the document object Model; sing XML and XSLT; asynchronous data retrieval using XmlhTtpreqUesT and Java Script binding everything together. The classic web application model works like this Most user actions in the interface trigger an Http request back to a web server thE server does some processing retrieving data, crunching numbers, talking to various legacy systems and then returns an HTML page to the client. It's a model adapted from the Web's origina l use as a hypertext medium but as fans of The Elements of User Experience know what makes the Web good for hypertext doesnt necessarily make it good for sof tware applications
rave about the interaction design of a product that wasn’t on the Web? (Okay, besides the iPod.) All the cool, innovative new projects are online. Despite this, Web interaction designers can’t help but feel a little envious of our colleagues who create desktop sof tware. Desktop applications have a richness and responsiveness that has seemed out of reach on the Web. The same simplicity that enabled the Web’s rapid proliferation also creates a gap between the experiences we can provide and the experiences users can get f rom a desktop application. That gap is closing. Take a look at Google Suggest. Watch the way the suggested terms update as you type, almost instantly. Now look at Google Maps. Zoom in. Use your cursor to grab the map and scroll around a bit. Again, everything happens almost instantly, with no waiting for pages to reload. Google Suggest and Google Maps are two examples of a new approach to web applications that we at Adaptive Path have been calling Ajax. The name is shorthand for Asynchronous JavaScript + XML, and it represents a fundamental shif t in what’s possible on the Web. Defining 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: • standards-based presentation using XHTML and CSS; • dynamic display and interaction using the Document Object Model; • data interchange and manipulation using XML and XSLT; • asynchronous data retrieval using XMLHttpRequest; • and JavaScript binding everything together. The classic web application model works like this: Most user actions in the interface trigger an HTTP request back to a web server. The server does some processing — retrieving data, crunching numbers, talking to various legacy systems — and then returns an HTML page to the client. It’s a model adapted from the Web’s original use as a hypertext medium, but as fans of The Elements of User Experience know, what makes the Web good for hypertext doesn’t necessarily make it good for sof tware applications
browser client user interface Javascript call browser client HTML+CSS data user interface ax engine Http request Http request http(s)transport http(s)transport HTML+Css data XML data web server web and/or XML server datastores, backend datastores, backend processing, legacy systems processing, legacy systems server-side systems server-side systems Aja veb application mode web application model Figure 1: The traditional model for web applications (left)compared to the Ajax This approach makes a lot of technical sense but it doesn't make for a great user experience. While the server is doing its thing what's the user doing Thats right, waiting. And at every step in a task the user waits some more Obviously if we were designing the Web from scratch for applications, we wouldnt make users wait around. Once an interf ace is loaded, why should the user interaction come to a halt every time the application needs something from the server? In fact, why should the user see the application go to the server at al? How Ajax is Different An Ajax application elim inates the start-stop-start-stop nature of interaction on the Web by introducing an intermed iary an ajax engine veen the user and the server. It seems like adding a layer to the application would make it less responsive, but the opposite is true
Figure 1: The traditional model for web applications (left) compared to the Ajax model (right). This approach makes a lot of technical sense, but it doesn’t make for a great user experience. While the server is doing its thing, what’s the user doing? That’s right, waiting. And at every step in a task, the user waits some more. Obviously, if we were designing the Web f rom scratch for applications, we wouldn’t make users wait around. Once an interface is loaded, why should the user interaction come to a halt every time the application needs something f rom the server? In fact, why should the user see the application go to the server at all? How Ajax is Different An Ajax application eliminates the start-stop-start-stop nature of interaction on the Web by introducing an intermediary — an Ajax engine — between the user and the server. It seems like adding a layer to the application would make it less responsive, but the opposite is true
Instead of loading a webpage at the start of the session the browser loads an Ajax engine written in Java Script and usua lly tucked away in a hidden frame This engine is responsible for both rendering the interf ace the user sees and communicating with the server on the users behalf. The ajax engine allows the user's interaction with the application to happen asynchronously inde pende nt of communication with the server. so the user is never staring at a blank browser window and an hourg lass icon, waiting around for the server to do something classic web application model (synchronous) client user activity user activty user activity me system proce system pr server Ajax web application model (asynchronous) client browser UI user activity 二 Ajax engine dient-side processing time server process processing processing Figure 2: The synchronous interaction pattern of a traditional web application (top)compared with the asynchronous pattern of an Ajax application( bottom)
Instead of loading a webpage, at the start of the session, the browser loads an Ajax engine — written in JavaScript and usually tucked away in a hidden f rame. This engine is responsible for both rendering the interface the user sees and communicating with the server on the user’s behalf . The Ajax engine allows the user’s interaction with the application to happen asynchronously — independent of communication with the server. So the user is never staring at a blank browser window and an hourglass icon, waiting around for the server to do something. Figure 2: The synchronous interaction pattern of a traditional web application (top) compared with the asynchronous pattern of an Ajax application (bottom)
Every user action that normally would generate an Hi TP request takes the form of a JavaScript call to the Ajax engine instead. Any response to a user action that doesnt require a trip back to the server such as simple data validation editing data in memory, and even some navigation- the eng ine hand les on its own. If the engine needs something from the server in order to respond - if it 's submitting data for processing loading additio nal interface code, or retrievin new data the engine makes those requests asynchronously, usually using XML, without stalling a user's interaction with the application Whos Using Ajax Google is making a huge investment in develo ping the ajax approach. All of the major products Google has introduced over the last year -Orkut, gmail, the latest beta version of Google Groups, Google Suggest, and Google Maps - are Ajax applications. (For more on the technical nuts and bolts of these Ajax imp lamentations, check out these excellent analyses of gmail, Google Suggest and Google Maps. Others are following suit: many of the features that people love in Flickr depend on Ajax, and Amazons A9. com search engine applies similar techniq rojects demonstrate that ajax is not only technically sound, but also practical for real-world applications. This isnt another technology that only And Ajax appl size, from the vel simple, single-function Google Suggest to the very complex and sophisticated wn work with Aj the last several months, and were realizing we've only scratched the surface of the rich interaction and responsiveness that Ajax applications can provide. Ajax is an important development for Web applications, and its importance is only going to grow. And because there are so many developers out there who already know how to use these technologies, we expect to see many more organizations following Googles lead in reaping the competitive advantage Ajax provides Moving Forward The biggest challenges in creating ajax applications are not technica l. the core Ajax technologies are mature, stable, and well understood Instead, the challenges are for the designers of these applications: to forget what we think
Every user action that normally would generate an HTTP request takes the form of a JavaScript call to the Ajax engine instead. Any response to a user action that doesn’t require a trip back to the server — such as simple data validation, editing data in memory, and even some navigation — the engine handles on its own. If the engine needs something f rom the server in order to respond — if it’s submitting data for processing, loading additional interface code, or retrieving new data — the engine makes those requests asynchronously, usually using XML, without stalling a user’s interaction with the application. Who’s Using Ajax Google is making a huge investment in developing the Ajax approach. All of the major products Google has introduced over the last year — Orkut, Gmail, the latest beta version of Google Groups, Google Suggest, and Google Maps — are Ajax applications. (For more on the technical nuts and bolts of these Ajax implementations, check out these excellent analyses of Gmail, Google Suggest, and Google Maps.) Others are following suit: many of the features that people love in Flickr depend on Ajax, and Amazon’s A9.com search engine applies similar techniques. These projects demonstrate that Ajax is not only technically sound, but also practical for real-world applications. This isn’t another technology that only works in a laboratory. And Ajax applications can be any size, f rom the very simple, single-function Google Suggest to the very complex and sophisticated Google Maps. At Adaptive Path, we’ve been doing our own work with Ajax over the last several months, and we’re realizing we’ve only scratched the surface of the rich interaction and responsiveness that Ajax applications can provide. Ajax is an important development for Web applications, and its importance is only going to grow. And because there are so many developers out there who already know how to use these technologies, we expect to see many more organizations following Google’s lead in reaping the competitive advantage Ajax provides. Moving Forward The biggest challenges in creating Ajax applications are not technical. The core Ajax technologies are mature, stable, and well understood. Instead, the challenges are for the designers of these applications: to forget what we think