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Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (June 2008) | "AJAX" redirects here. For other uses, see Ajax. Ajax (asynchronous JavaScript and XML), or AJAX, is a group of interrelated web development techniques used for creating interactive web applications. A primary characteristic is the increased responsiveness of web pages achieved by exchanging small amounts of data with the server "behind the scenes" so that entire web pages do not have to be reloaded each time there is a need to fetch data from the server. This is intended to increase the web page's interactivity, speed, functionality and usability. // Ajax may refer to: Ajax the Great as a well known hero from the Trojan war and son of Telamon Ajax the Lesser son of the king of Locris, and another hero in the Trojan war Ajax (missionary), Arian missionary who converted the pagan Suevi c. ...
JavaScript is a scripting language most often used for client-side web development. ...
The Extensible Markup Language (XML) is a general-purpose markup language. ...
Web development is a broad term for any activities related to developing a web site for the World Wide Web or an intranet. ...
In software engineering, a web application is an application delivered to users from a web server over a network such as the World Wide Web or an intranet. ...
Usability is a term used to denote the ease with which people can employ a particular tool or other human-made object in order to achieve a particular goal. ...
Ajax is asynchronous, in that extra data is requested from the server and loaded in the background without interfering with the display and behavior of the existing page. JavaScript is the scripting language in which Ajax function calls are usually made. Data is retrieved using the XMLHttpRequest object that is available to scripting languages run in modern browsers, or, alternatively, through the use of Remote Scripting in browsers that do not support XMLHttpRequest. In any case, it is not required that the asynchronous content be formatted in XML. Asynchrony is the state of not being synchronized. ...
JavaScript is a scripting language most often used for client-side web development. ...
A scripting language, script language or extension language, is a programming language that controls software application. ...
XMLHttpRequest (XHR) is an API that can be used by JavaScript, and other web browser scripting languages to transfer XML and other text data to and from a web server using HTTP, by establishing an independent and asynchronous communication channel between a web pages Client-Side and Server-Side. ...
In strictly mathematical branches of computer science the term object is used in a purely mathematical sense to refer to any thing. While this interpretation is useful in the discussion of abstract theory, it is not concrete enough to serve as a primitive datatype in the discussion of more concrete...
Remote Scripting [1] is a technology developed by Microsoft. ...
The Extensible Markup Language (XML) is a general-purpose markup language. ...
Ajax is a cross-platform technique usable on many different operating systems, computer architectures, and web browsers as it is based on open standards such as JavaScript and the Document Object Model (DOM). There are free and open source implementations of suitable frameworks and libraries (see List of JavaScript libraries). A cross-platform (or platform independent) programming language, software application or hardware device works on more than one system platform (e. ...
An operating system (OS) is a software that manages computer resources and provides programmers with an interface used to access those resources. ...
A typical vision of a computer architecture as a series of abstraction layers: hardware, firmware, assembler, kernel, operating system and applications (see also Tanenbaum 79). ...
An example of a Web browser (Mozilla Firefox) A web browser is a software application that enables a user to display and interact with text, images, videos, music and other information typically located on a Web page at a website on the World Wide Web or a local area network. ...
This article or section cites very few or no references or sources. ...
Hierarchy of objects in an example HTML DOM - Document Object Model The Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats. ...
Free software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with minimal restrictions only to ensure that further recipients can also do these things. ...
The logo of the Open Source Initiative For other uses, see open source. ...
A software framework is a reusable design for a software system (or subsystem). ...
Illustration of an application which may use libvorbisfile. ...
It has been suggested that this article or section be merged into List of web application frameworks#JavaScript. ...
History
While the term "Ajax" was arguably coined in 2005 by the company Adaptive Path and first made it into the public sphere in the article "Ajax: A New Approach to Web Applications",[1] techniques for the asynchronous loading of content on an existing Web page date back as far as the src attribute, which could take any external URL and load a page containing JavaScript that manipulated the parent page, resulting in Ajax-like effects. This set of client-side technologies was usually grouped together under the generic term DHTML.[clarify][citation needed] // Uniform Resource Locator (URL) formerly known as Universal Resource Locator, is a technical, Web-related term used in two distinct meanings: In popular usage and many technical documents, it is a synonym for Uniform Resource Identifier (URI); Strictly, the idea of a uniform syntax for global identifiers of network-retrievable...
Dynamic HTML or DHTML is a collection of technologies used together to create interactive and animated web sites by using a combination of a static markup language (such as HTML), a client-side scripting language (such as JavaScript), a presentation definition language (Cascading Style Sheets, CSS), and the Document Object...
Microsoft's Remote Scripting, introduced in 1998, acted as a more elegant replacement for these techniques, with data being pulled in by a Java applet with which the client side could communicate using JavaScript. This technique worked on both Internet Explorer 4 and Netscape Navigator 4 and onwards. Microsoft then created the XMLHttpRequest object in Internet Explorer 5 and first took advantage of these techniques using XMLHttpRequest in Outlook Web Access supplied with the Microsoft Exchange Server 2000 release. Remote Scripting [1] is a technology developed by Microsoft. ...
A Java applet is an applet delivered in the form of Java bytecode. ...
Windows Internet Explorer (formerly Microsoft Internet Explorer abbreviated MSIE), commonly abbreviated to IE, is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems starting in 1995. ...
Netscape Navigator, also known as Netscape, was a proprietary web browser that was popular during the 1990s. ...
Outlook Web Access (OWA) is a webmail service of Microsoft Exchange Server 5. ...
Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft. ...
The Web development community, first collaborating for remote scripting to enable consistent results across different browsers, created in 2002 a user-community modification to Microsoft Remote Scripting which was created to replace the Java applet with XMLHttpRequest.[2]
Remote Scripting frameworks such as ARSCIF[3] surfaced in 2003 not long before Microsoft introduced callbacks in ASP.NET.[4] ASP.NET logo ASP.NET is a web application framework marketed by Microsoft that programmers can use to build dynamic web sites, web applications and XML web services. ...
In addition, the World Wide Web Consortium (W3C) has several recommendations that also allow for dynamic communication between a server and user agent, though few of them are well supported.[citation needed] These would include: WWWC redirects here. ...
- The object element defined in HTML 4 for embedding arbitrary content types into documents (replaces inline frames under XHTML 1.1)
- The Document Object Model (DOM) Level 3 Load and Save Specification[5]
Rationale The core reason to use Ajax-style programming is to overcome the page loading requirements of HTML/HTTP-mediated web pages. Ajax creates the necessary initial conditions for the evolution of complex, intuitive, dynamic, data-centric user interfaces in web pages. Indeed, much of the Web's innovation and evolution during the Web 2.0 era has relied upon and benefited immensely from the capabilities of an Ajax platform.[citation needed] Web 2. ...
Web pages, unlike native applications, are loosely coupled, meaning that the data they display are not tightly bound to data sources and must be first marshaled (set out in proper order) into an HTML page format before they can be presented to a user agent on the client machine.[clarify] For this reason, web pages have to be re-loaded each time a user needs to view different datasets. By using the XMLHttpRequest object to request and return data without a re-load, a programmer bypasses this requirement and makes the loosely coupled web page behave much like a tightly coupled application, but with a more variable lag time for the data to pass through a longer "wire" to the remote web browser. Loosely coupled describes a resilient relationship between two or more computer systems that are exchanging data. ...
A user agent is the client application used with a particular network protocol; the phrase is most commonly used in reference to those which access the World Wide Web. ...
For example, in a classic desktop application, a programmer has the choice of populating a tree view control with all the data needed when the form initially loads, or with just the top-most level of data—which would load more quickly, especially when the dataset is very large.[clarify] In the second case, the application would fetch additional data into the tree control depending on which item the user selects. This functionality is difficult to achieve in a web page without Ajax.[citation needed] To update the tree based on a user's selection would require the entire page to re-load, leading to a very jerky, non-intuitive feel for the web user who is browsing the data in the tree. Information in this article or section has not been verified against sources and may not be reliable. ...
Application software is a subclass of computer software that employs the capabilities of a computer directly and thoroughly to a task that the user wishes to perform. ...
A tree view or an outline view is a graphical user interface element (widget) that presents a hierarchial view of information. ...
Advantages
Bandwidth usage By generating the HTML locally within the browser, and only bringing down JavaScript calls and the actual data, Ajax web pages can appear to load relatively quickly since the payload coming down is much smaller in size, and the rest of the layout does not have to be redrawn on each update. An example of this technique is a large result set where multiple pages of data exist. With Ajax, the HTML of the page (e.g., a table structure with related <tr> and <td> tags) can be produced locally in the browser, not brought down with the first page of the document. In addition to "load on demand" of contents, some web-based applications load stubs of event handlers and then load the functions on the fly. This technique significantly cuts down the bandwidth consumption for web applications.[6]
Separation of data, format, style, and function A less specific benefit of the Ajax approach is that it tends to encourage programmers to clearly separate the methods and formats used for the different aspects of information delivery via the web. Although Ajax can appear to be a jumble of languages and techniques, and programmers are free to adopt and adapt whatever works for them, they are generally propelled by the development motive itself to adopt separation among the following:[citation needed] - Raw data or content to be delivered, which is normally embedded in XML and sometimes derived from a server-side database.
- Format or structure of the webpage, which is almost always built in HTML or XHTML and is then reflected and made available to dynamic manipulation in the DOM.
- Style elements of the webpage: everything from fonts to picture placement are derived by reference to embedded or referenced CSS.
- Functionality of the webpage, which is provided by a combination of:
- Javascript on the client browser (Also called DHTML),
- Standard HTTP and XMLHttp or client-to-server communication, and
- Server-side scripting and/or programs using any suitable language preferred by the programmer to receive the client's specific requests and respond appropriately.
This article is principally about managing and structuring the collections of data held on computers. ...
JavaScript is a scripting language most often used for client-side web development. ...
Dynamic HTML or DHTML designates a technique of creating interactive web sites by using a combination of the static markup language HTML, a client-side scripting language (such as JavaScript) and the style definition language Cascading Style Sheets. ...
Disadvantages
Browser integration The dynamically created page does not register itself with the browser history engine, so triggering the "Back" function of the users' browser might not bring the desired result; rather than returning the user to an earlier state of the Ajax-enabled page, the back button would return the user to the last page visited before the Ajax-enabled page.
Developers have implemented various solutions to this problem. These solutions can involve using invisible IFrames to invoke changes that populate the history used by a browser's back button. Google Maps, for example, performs searches in an invisible IFrame and then pulls results back into an element on the visible web page.[citation needed] IFRAME is a tag used in web page designing. ...
Google Maps (for a time named Google Local) is a free web mapping service application and technology provided by Google that powers many map-based services including the Google Maps website, Google Ride Finder and embedded maps on third-party websites via the Google Maps API. It offers street maps...
Dynamic web page updates also make it difficult for a user to bookmark a particular state of the application. Solutions to this problem exist, many of which use the URL fragment identifier (the portion of a URL after the '#') to keep track of, and allow users to return to, the application in a given state.[citation needed] This is possible because many browsers allow JavaScript to update the fragment identifier of the URL dynamically, so that Ajax applications can maintain it as the user changes the application's state. This solution also improves back-button support. It is not, however, a complete solution.[citation needed] A fragment identifier is a short string of characters that refers to a resource that is subordinate to another, primary resource. ...
Response-time Network latency, the interval between user request and server response, must be considered carefully during Ajax development. Without clear feedback to the user,[7] preloading of data and proper handling of the XMLHttpRequest object, users might experience delays in the interface of the web application, something which they might not expect or understand. Additionally, when an entire page is rendered there is a brief moment of re-adjustment for the eye as content changes. The lack of this re-adjustment with smaller portions of the screen changing makes the latency more apparent.[clarify] The use of visual feedback (such as throbbers) to alert the user of background activity and/or preloading of content and data are often-suggested solutions to these latency issues. Latency is a time delay between the moment something is initiated, and the moment one of its effects begins. ...
A throbber from the Netscape web browser A throbber is a graphic usually found in the top-right corner of the graphical user interface of a computer program (especially a web browser) that animates to show the user that the program is performing an action (such as downloading a web...
Search engine optimization Websites that use Ajax to load data which should be indexed by search engines must be careful to provide equivalent data for clients without JavaScript, as search engines do not generally execute the JavaScript code required for Ajax functionality.[citation needed] This problem is not specific to Ajax, as the same issue occurs with sites that provide dynamic data as a full-page refresh in response to, say, a form submit. (The general problem is sometimes called the deep web.)Using mod_rewrite, this issue can be resolved[8]. The success of the Google search engine was mainly due to its powerful PageRank algorithm and its simple, easy-to-use interface. ...
The deep Web (or Deepnet, invisible Web or hidden Web) refers to World Wide Web content that is not part of the surface Web indexed by search engines. ...
A rewrite engine is a piece of web server software used to modify URLs, for a variety of purposes. ...
Reliance on JavaScript and the DOM Ajax relies on JavaScript and the browser's Document Object Model (DOM), which is often implemented differently by different browsers or versions of a particular browser. Because of this, sites that use JavaScript may need to be tested in multiple browsers to check for compatibility issues. It's common to see JavaScript code written twice—one part for Internet Explorer, another part for Mozilla compatibles[citation needed]—although this is less true with the release of IE7 and with the now-common use of JavaScript libraries such as Prototype or jQuery, which abstract browser-specific differences from the web developer. Hierarchy of objects in an example HTML DOM - Document Object Model The Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats. ...
A cross-platform (or platform independent) programming language, software application or hardware device works on more than one system platform (e. ...
The Prototype JavaScript Framework is a JavaScript framework created by Sam Stephenson that provides an Ajax framework and other utilities. ...
jQuery is a lightweight JavaScript library that emphasizes interaction between JavaScript and HTML. It was released January 2006 at BarCamp NYC by John Resig. ...
The level of IDE support for JavaScript used to be poor,[citation needed] although it is changing with more wide-spread use of tools like Drosera, Firebug, Microsoft Script Debugger and Venkman. An integrated development environment (IDE), also known as integrated design environment and integrated debugging environment, is a programming environment that has been packaged as an application program,that assists computer programmers in developing software. ...
WebKit is an application framework included with Mac OS X v10. ...
Firebug 1. ...
Microsoft Script Debugger is a lightweight JScript debugger provided for free of charge. ...
Venkman is the JavaScript debugger component of the Mozilla web browser. ...
Finally, if the user has switched off JavaScript support, pages designed to use Ajax may not function.
Web analytics Many web analytics solutions expect a new page to be loaded whenever new or updated content is displayed to the user, and after each step in a process such as a check-out.[citation needed] Since Ajax alters this process, developers must take care to instrument a page or a portion thereof so that it can be accurately tracked. Analytics systems which can track events other than simple page views, such as clicks of buttons or links, are most able to accommodate Ajax-using sites.[citation needed][clarify] Web analytics is the study of the behaviour of website visitors. ...
Accessibility -
Main article: WAI-ARIA Non-Ajax users would ideally continue to load and manipulate the whole page as a fall back, enabling the developers to preserve the experience of users in non-Ajax environments (including all relevant accessibility concerns) while giving those with capable browsers a much more responsive experience.[clarify] For this reason it is advised to first develop a full application without Ajax, and implement Ajax enhancements as an addition only (see: Progressive enhancement methodology).[citation needed] The same counts for JavaScript in general, which can be disabled in most browsers. Progressive Enhancement is a label for a particular strategy for Web design that emphasizes accessibility, semantic markup, and external stylesheet and scripting technologies, in a layered fashion that allows all to access the basic content and functionality of a Web page, using any browser or Internet connection, while also enabling...
Because many people[weasel words] consider it unreasonable to advise against the use of JavaScript in modern web applications, the W3C Web Accessibility Initiative (WAI) is working on a specification for Accessible Rich Internet Applications (ARIA). In effect, ARIA allows web pages, or portions of web pages, to declare themselves as applications rather than as documents. This allows Ajax interactions and other types of JavaScript-enabled UI controls to interact with assistive technology, like screen readers for the vision-impaired.
One early user agent implementation is Firefox 3, which maps WAI-ARIA to the accessibility API of the underlying operating system, making it possible for screen readers to treat ARIA widgets in much the same way as the widgets found in client-side software. Another early implementation is Fire Vox, an extension that turns Firefox into a self-voicing browser. Since Fire Vox operates directly on the DOM and does not use the operating system's accessibility API, it can handle WAI-ARIA features, such as live regions, which have no mapping to traditional desktop applications. A user agent is the client application used with a particular network protocol; the phrase is most commonly used in reference to those which access the World Wide Web. ...
Hierarchy of objects in an example HTML DOM - Document Object Model The Document Object Model (DOM) is a platform- and language-independent standard object model for representing HTML or XML and related formats. ...
Ajax libraries and toolkits are also adopting ARIA. Notable examples include Google Web Toolkit, Backbase and Dojo Toolkit.[citation needed] In addition, AxsJAX, a JavaScript library which focuses on web-application accessibility, includes several abstractions built on top of ARIA. The Google Web Toolkit is an open source toolkit allowing developers to create Ajax applications in the Java programming language [1]. GWT supports rapid client/server development and debugging in any Java IDE. In a subsequent deployment step, the GWT compiler translates a working Java application into equivalent JavaScript that...
This article is being considered for deletion in accordance with Wikipedias deletion policy. ...
To meet Wikipedias quality standards, this article or section may require cleanup. ...
See also // An Ajax framework is a framework that helps to develop web applications that use Ajax, a collection of technologies used to build dynamic web pages on the client side. ...
Google Gears is a beta service offered by Google to enable access to online services while off-line. ...
Progressive Enhancement is a label for a particular strategy for Web design that emphasizes accessibility, semantic markup, and external stylesheet and scripting technologies, in a layered fashion that allows all to access the basic content and functionality of a Web page, using any browser or Internet connection, while also enabling...
Reverse Ajax, shorthand for Reverse Asynchronous JavaScript and XML, is a web development technique for creating interactive web applications. ...
For the geographical term, see ria. ...
XMLHttpRequest (XHR) is an API that can be used by JavaScript, and other web browser scripting languages to transfer XML and other text data to and from a web server using HTTP, by establishing an independent and asynchronous communication channel between a web pages Client-Side and Server-Side. ...
References Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...
is the 49th day of the year in the Gregorian calendar. ...
2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Common Era (or Anno Domini), in accordance with the Gregorian calendar. ...
is the 170th day of the year (171st in leap years) in the Gregorian calendar. ...
Also see: 2002 (number). ...
is the 169th day of the year (170th in leap years) in the Gregorian calendar. ...
Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...
is the 213th day of the year (214th in leap years) in the Gregorian calendar. ...
Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...
is the 213th day of the year (214th in leap years) in the Gregorian calendar. ...
The Microsoft Developer Network (MSDN) is an information service from Microsoft for software developers. ...
Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...
is the 220th day of the year (221st in leap years) in the Gregorian calendar. ...
Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...
is the 213th day of the year (214th in leap years) in the Gregorian calendar. ...
Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...
is the 15th day of the year in the Gregorian calendar. ...
2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Common Era (or Anno Domini), in accordance with the Gregorian calendar. ...
is the 167th day of the year (168th in leap years) in the Gregorian calendar. ...
Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...
is the 234th day of the year (235th in leap years) in the Gregorian calendar. ...
Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...
is the 202nd day of the year (203rd in leap years) in the Gregorian calendar. ...
External links The Open Directory Project (ODP), also known as dmoz (from , its original domain name), is a multilingual open content directory of World Wide Web links owned by Netscape that is constructed and maintained by a community of volunteer editors. ...
For other uses, see Black hat (disambiguation). ...
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