AJAX - Union of technologies to increase the interactivity of the web site

AJAX incorporates several technologies to work. It is XHTML and CSS for presentation based on a standard Document Object Model for dynamic display and interaction, XML and XSLT for data interchange and manipulation; XMLHttpRequest for asynchronous data retrieval, and JavaScript to bind everything together.

Since AJAX allows asynchronous action, the loading of small amounts of new data will not interfere with normal page loading. AJAX allows web experience more responsive in that it allows your web page to exchange small amounts of data with the server as you view the page.

With AJAX, your actions send a request to JavaScript that trigger action - usually a request for data recovery - which is answered by the web page as an XML response. The web page changes accordingly, without reloading the entire page.

In a classic web application, user actions trigger an HTTP request to the web server. The server processes the request and responds to the request to load a new HTML page appropriate for the user.

With AJAX, there is no need to wait for your server to reload the page according to your requests. AJAX allows the page to process your request and therefore make minor changes without having to reload the entire page. AJAX reduces the waiting time and makes the web experience more dynamic.

When you load a Web page that uses AJAX, the browser loads the AJAX engine that also makes the interface the user sees and communicates with the server at the same time. The user can interact with the application asynchronously, every action you make a request generates JavaScript, which triggers a response from the AJAX engine.

Since AJAX is capable of asynchronous action, the user interaction with the web page does not stall. You are not left staring at a blank browser window, while the server processes requests.

The element is provided by asynchronous AJAX XMLHttpRequest. This technology allows the browser to make requests for data without reloading the page. This eliminates the need for page refreshing.

Web pages are usually loosely coupled. The data show that there are bound to data sources and must first be defined properly in an HTML format before they can be presented in a browser window. This means that, in the traditional format, a web page needs to be reloaded each time you need to view different sets of data. With XMLHttpRequest a programmer can bypass this requirement.

AJAX web pages load quickly since the payload is smaller drop size and the rest of the layout should not be redrawn when it requires a page refresh. As such the use of the bandwidth and the requirements of a page that uses AJAX are minimized.

Another advantage of AJAX is that the use of this platform means that programmers need to clearly separate the methods and formats used for aspects of the provision of information.

Programmers who use AJAX can adopt or adapt any technique work for them, but must adopt the separation of raw data or content to be delivered, format or structure of the web page; style elements of the web page, and functionality of the web page.

How AJAX is a new application, it is still evolving and as such is vulnerable to some defects, usually with reference to its interaction with certain web applications.

A page created AJAX is not recorded in the history of a web browser. As such, triggering the function rear could not bring the desired result. The programmers have tried to use the invisible iframe to invoke changes that populate the history used by a browser's Back button, but not every website has them still.

It 's too difficult to add a page using AJAX. However, a solution to this would be the use of a fragment identifier URL. Many browsers allow JavaScript to update the fragment identifier of a URL dynamically and how these changes made by users to a page using an AJAX application can be maintained.

If you want to use an AJAX application on your website, you must take into account the network latency. Network latency is the interval between user request and server response. Some factors may increase the network latency of a web page and cause delays in the web application interface. If the user is not aware of AJAX properties may result in them assuming that there is something wrong with the page.

Furthermore, when a Web page is rendered or modified by a request, there is a brief moment of re-adjustment when the content changes. This can also cause confusion for the viewer. The use of visual clues and warnings to make the user aware of the background activity related to an AJAX application is recommended.

While AJAX is based on JavaScript for its dynamic interactions; JavaScript can cause its share of problems. JavaScript can be implemented differently by different browsers and as such there may be compatibility problems. If your browser is incompatible with user-JavaScript portions of the site may be distorted or simply defaced.

Search engines, as a rule, do not perform the necessary JavaScript for AJAX functionality. Web sites that use AJAX to load data must provide equivalent data to Sitemaps public, linked URL that search engines can read.

AJAX can also be a problem with web analytics systems. Analysis systems that enable the tracking of events other than display a page as simple as the click of a button or link, are more likely to be able to host a site that makes extensive use of Ajax ....