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
we know about the lim itations of the Web, and begin to imagine a w ider, richel range of possibilities It's going to be fun Ajax Q&A March 13, 2005: Since we first published Jesse's essay we've received an enormous amount of correspondence from readers with questions about ajax In this Q&A, Jesse responds to some of the most common queries. Q. Did Adaptive Path invent Ajax? Did Google? Did Adaptive Path help build Googles Ajax applications? A. Neither Adaptive Path nor google invented Ajax Googles recent products are simply the highest-prof ile examples of Ajax applications. Adaptive Path was not involved in the development of Google's Ajax applications but we have been doing Ajax work for some of our other clients Q. Is Adaptive Path selling ajax components or trademarking the name? Where can i download it? A. Ajax isnt something you can dow load It's an approach -a way of thinking about the architecture of web applications using certain technologies. Neither the ajax name nor the approach are proprietary to Adaptive path Q. Is Ajax just another name for XmlhTtpreqUesT? A. No. XmlhTtpreqUesT is only part of the Ajax equation XmlHttpreQuesT is the technical component that makes the asynchronous server communication possible: Ajax is our name for the overall approach described in the article which relies not only on XmlhTtpreQuesT, but on csS, Dom, and other Q. Why did you feel the need to give this a name? A. I needed something shorter than Asynchronous Javascript+ css+dom+ XmlhTtpreQuesT to use when discussing this approach with clients
we know about the limitations of the Web, and begin to imagine a wider, richer range of possibilities. It’s going to be fun. Ajax Q&A March 13, 2005: Since we first published Jesse’s essay, we’ve received an enormous amount of correspondence f rom readers with questions about Ajax. In this Q&A, Jesse responds to some of the most common queries. Q. Did Adaptive Path invent Ajax? Did Google? Did Adaptive Path help build Google’s Ajax applications? A. Neither Adaptive Path nor Google invented Ajax. Google’s recent products are simply the highest-profile examples of Ajax applications. Adaptive Path was not involved in the development of Google’s Ajax applications, but we have been doing Ajax work for some of our other clients. Q. Is Adaptive Path selling Ajax components or trademarking the name? Where can I download it? A. Ajax isn’t something you can download. It’s an approach — a way of thinking about the architecture of web applications using certain technologies. Neither the Ajax name nor the approach are proprietary to Adaptive Path. Q. Is Ajax just another name for XMLHttpRequest? A. No. XMLHttpRequest is only part of the Ajax equation. XMLHttpRequest is the technical component that makes the asynchronous server communication possible; Ajax is our name for the overall approach described in the article, which relies not only on XMLHttpRequest, but on CSS, DOM, and other technologies. Q. Why did you feel the need to give this a name? A. I needed something shorter than “Asynchronous JavaScript+CSS+DOM+XMLHttpRequest” to use when discussing this approach with clients
Q. Techniques for asynchronous server communication have been around for years. What makes Ajax a"new"approach? hat's new is the prominent use of these techniques in real-world plications to change the fundamental interaction model of the Web. Ajax taking hold now because these technologies and the industrys understanding of how to deploy them most effectively have taken time to develop Q. Is ajax a technology platform or is it an architectural style? It's both. ajax is a set of technologies being used together in a particular way Q. What kinds of applications is Ajax best suited for? A. We dont know yet. Because this is a relatively new approach, our understanding of where Ajax can best be applied is still in its inf ancy Sometimes the traditional web application model is the most appropriate on a problem Q. Does this mean Adaptive Path is anti-Flash? A. Not at all. Macromedia is an Adaptive Path client and we've long been supporters of Flash technology. As Ajax matures, we expect that sometimes Ajax will be the better solution to a particular problem and sometimes Flash will be the better solution. Were also interested in exploring ways the technologies can be mixed (as in the case of Flickr, which uses both) Q. Does Ajax have sign if icant accessibility or browser compatib il ity lim ita tions? Do Ajax applications break the back button? Is ajax compatible w ith REST? Are there security considerations with Ajax development? Can Ajax applications b made to work for users who have Java Script turned off? A. The answer to all of these questions is "maybe". Many developers are already working on ways to address these concerns. We think theres more work to be done to determine all the limitations of Ajax, and we expect the ajax development community to uncover more issues like these along the way Q. Some of the Google examples you cite dont use XML at all. do i have to use XML and/or XsLT in an Ajax application?
Q. Techniques for asynchronous server communication have been around for years. What makes Ajax a “new” approach? A. What’s new is the prominent use of these techniques in real-world applications to change the fundamental interaction model of the Web. Ajax is taking hold now because these technologies and the industry’s understanding of how to deploy them most ef fectively have taken time to develop. Q. Is Ajax a technology platform or is it an architectural style? A. It’s both. Ajax is a set of technologies being used together in a particular way. Q. What kinds of applications is Ajax best suited for? A. We don’t know yet. Because this is a relatively new approach, our understanding of where Ajax can best be applied is still in its infancy. Sometimes the traditional web application model is the most appropriate solution to a problem. Q. Does this mean Adaptive Path is anti-Flash? A. Not at all. Macromedia is an Adaptive Path client, and we’ve long been supporters of Flash technology. As Ajax matures, we expect that sometimes Ajax will be the better solution to a particular problem, and sometimes Flash will be the better solution. We’re also interested in exploring ways the technologies can be mixed (as in the case of Flickr, which uses both). Q. Does Ajax have significant accessibility or browser compatibility limitations? Do Ajax applications break the back button? Is Ajax compatible with REST? Are there security considerations with Ajax development? Can Ajax applications be made to work for users who have JavaScript turned of f ? A. The answer to all of these questions is “maybe”. Many developers are already working on ways to address these concerns. We think there’s more work to be done to determine all the limitations of Ajax, and we expect the Ajax development community to uncover more issues like these along the way. Q. Some of the Google examples you cite don’t use XML at all. Do I have to use XML and/or XSLT in an Ajax application?
A. No. XML is the most fully-deve loped means of getting data in and out of an Ajax client but there's no reason you couldnt accomplish the same effects using a technology like JavaScript object Notation or any similar means of structuring data for interchange. Q. Are Ajax applications easier to develop than traditional web applications A. Not necessarily. Ajax applications inevitably involve running complex JavaScript code on the client. Making that complex code eff icient and bug-free is not a task to be taken lightly, and better development tools and frameworks will be needed to help us meet that challenge Q. Do Ajax applications a lways de liver a better experience than traditional web applications? A. Not necessarily. Ajax gives interaction designers more flexibility. However, the more power we have, the more caution we must use in exercising it. We must be careful to use ajax to enhance the user experience of our applications, not degrade it. Jesse James Garrett is President and a founder of Adaptive Pa th. He is the author of the widely-referenced book The elements of User Experience. Jesses other essays include The Nine Pillars of Successful Web Teams and Six Design Lessons From the Apple Store To get essays like this one delivered directly to your inbox subscribe to our email newsletter. For more, check out our blog
A. No. XML is the most fully-developed means of getting data in and out of an Ajax client, but there’s no reason you couldn’t accomplish the same ef fects using a technology like JavaScript Object Notation or any similar means of structuring data for interchange. Q. Are Ajax applications easier to develop than traditional web applications? A. Not necessarily. Ajax applications inevitably involve running complex JavaScript code on the client. Making that complex code efficient and bug-f ree is not a task to be taken lightly, and better development tools and f rameworks will be needed to help us meet that challenge. Q. Do Ajax applications always deliver a better experience than traditional web applications? A. Not necessarily. Ajax gives interaction designers more flexibility. However, the more power we have, the more caution we must use in exercising it. We must be careful to use Ajax to enhance the user experience of our applications, not degrade it. Jesse James Garrett is President and a founder of Adaptive Path. He is the author of the widely-referenced book The Elements of User Experience. Jesse’s other essays include The Nine Pillars of Successful Web Teams and Six Design Lessons From the Apple Store. To get essays like this one delivered directly to your inbox, subscribe to our email newsletter. For more, check out our blog
Jesse James Garrett is President and a founder of Adaptive path. He is the author of the widely-referenced book The elements of User Experience. Jesses other 's include The Nine pillars of Successful Web Teams and six Design Lessons From the Apple store To get essays like this one delivered directly to your inbox subscribe to our email newsletter. For more, check out our blog. Printer-friendly version Syndicate this site Powered by Movable Type 2. 661 This work is licensed under a creative commons License Email Newsletter Sign up to receive essays, appearance dates and other news from Adaptive Path Your email address submit C 2007 Adaptive Path, LLC Adaptive Path 363 Brannan St. San Francisco, CA 941071-415-495-8270 http://www.adaptivepath.com/publications/essays/archives/000385.php
Jesse James Garrett is President and a founder of Adaptive Path. He is the author of the widely-referenced book The Elements of User Experience. Jesse’s other essays include The Nine Pillars of Successful Web Teams and Six Design Lessons From the Apple Store. To get essays like this one delivered directly to your inbox, subscribe to our email newsletter. For more, check out our blog. Printer-friendly version Syndicate this site Powered by Movable Type 2.661 This work is licensed under a Creative Commons License. Email Newsletter Sign up to receive essays, appearance dates, and other news from Adaptive Path. Your email address: submit © 2007 Adaptive Path, LLC Adaptive Path | 363 Brannan St. | San Francisco, CA 94107 | 1-415-495-8270 http://www.adaptivepath.com/publications/essays/archives/000385.php