Ajax Courses Online

About

Ajax , short for "Asynchronous JavaScript and XML") is a set of web development techniques using many web technologies on the client-side to create asynchronous web applications. With Ajax, web applications can send and retrieve data from a server asynchronously (in the background) without interfering with the display and behavior of the existing page. By decoupling the data interchange layer from the presentation layer, Ajax allows web pages and, by extension, web applications, to change content dynamically without the need to reload the entire page. In practice, modern implementations commonly utilize JSON instead of XML.

Ajax is not a single technology, but rather a group of technologies. HTML and CSS can be used in combination to mark up and style information. The webpage can then be modified by JavaScript to dynamically display—and allow the user to interact with—the new information. The built-in XMLHttpRequest object, or since 2017 the new "fetch()" function within JavaScript, is commonly used to execute Ajax on webpages, allowing websites to load content onto the screen without refreshing the page. Ajax is not a new technology, or a different language, just existing technologies used in new ways.

Content

• History
• Technologies
• Drawbacks
• Examples
  • JavaScript example
  • jQuery example
  • Fetch example

About

Handling HTML returned from AJAX is surprisingly difficult. Since XMLHttpRequest was designed to work with well-formed XML, attempting to parse an HTML page with the responseXML property almost invariably produces an XML parse error. The responseText property contains the HTML source, of course, and one can attempt to parse this with regular string functions or regular expressions. However, the XMLHttpRequest object does not provide an easy way to parse returned HTML with DOM operations.

Content

• Introduction
• Parsing HTML
• Node Creation

About

AjaxDroppable represents the second half of the drag-and-drop implementation in the Ajax framework. AjaxDroppable also uses a WOComponentContent, so any content that you would like to appear in the drop target should be inside of AjaxDroppable's web object tags.

Content

• Introduction and features
• Wonder Bindings
• Scriptaculous Bindings

About

AjaxAccordian provides a wrapper around the Rico framework's accordian control. A demo of the control is available in this course. The WO version consists of an AjaxAccordian component that contains a series of AjaxAccordianTab components.

Content

• Introduction and features
• Wonder Bindings
• Rico Bindings

About

AJAX is nowadays one of the most common used words in the WEB 2.0 era. While the historic remains of it are not really clear (similar logic to manipulate parts of a webpage was already thought of as DHTML, long before the term AJAX existed and surprisingly even using some type of DOM later on) it is now one of the most important technologies used by modern webdesigners. But what does AJAX mean? - In short, AJAX stands for Asynchronous JavaScript and XML. It describes a concept of asynchronous data transfer (here: data encapsulated in XML) between the client (usually a webbrowser) and a server to only exchange/ alter a part of the webpage without the need of a full page reload. That means the browser will issue an XMLHttpRequest in the background and receive only a part of the page - usually tied to one or more html-tags holding UIDs.

The following are the main components of the Ajax programming pattern.

• JavaScript - The most popular scripting language on the Web and supported by all major browsers. Ajax applications are built-in JavaScript.
• Document Object Model (DOM) - Defines the structure of a web page as a set of programmable objects. In Ajax programming, the DOM allows us to redraw portions of the page.
• Cascading Style Sheets (CSS) - Provides a way to define the visual appearance of elements on a web page.
• XMLHttpRequest - Allows a client-side script to perform an HTTP request, effectively eliminating a full-page refresh or postback in Ajax applications.
• XML - It is sometimes used as the format for transferring data between the server and client, but other text-based formats work as well.

Ajax offers a number of advantages. Some of the most important are listed below.

• Lower demand of bandwidth: The fact that it is not necessary to re-load a page completely when additional information is requested allows minimizing the data transfer. The demand of bandwidth is also reduced by producing HTML locally within the browser (note: however as we have additional overhead produced by the embedding of the JavaScript this is only true in case of more than one or two page requests from the same site).
• Browser plug-in not necessary: Ajax runs with every browser which supports JavaScript. There is no additional plug-in needed. This is an advantage over technologies like Shockwave or Flash (note: in some cases however it is possible that some browsers behave different; especially IE prior to version 6 is known for odd behavior).
• Separation of data and formats: This allows the web application to be more efficient. Programmers can separate the methods and formats for delivering information over the web. So they can use a language they are familiar with (note: the reason for this is CSS and not AJAX).
• Websites more user-friendly: Because of the minimized data transfer the response to the actions of the user is much faster. Furthermore interfaces built with Ajax can be more user-friendly (note: however, AJAX without fallback to plain-vanilla HTML request-response cycle is infamous for being a big drawback to barrier free web design)

About

AjaxSortableList provides support for automatic reordering of an NSArray based on an Ajax drag-and-drop list. AjaxSortableList is a WOComponentContent. By default, it renders an unordered list.

Content

• Introduction and features
• Wonder Bindings
• Scriptaculous Bindings