Asynchronous JavaScript and XML: What Is AJAX?
AJAX is a combination of web development and programming technologies for creating fast-loading interactive websites and web applications based on XML, HTML, CSS and Java Script. Using Ajax technologies professional web designers and web developers are able to create modern web applications with cutting-edge accessibility and interactivity.
Developing Ajax Web Applications
AJAX stands for Asynchronous JavaScript and XML. The technology allows developing better and quicker applications. The key is that Ajax web apps retrieve data from a server asynchronously without interfering with the display of the existing web page.
In other words, the asynchronous nature of AJAX allows the browser to exchange data with a server while the user is doing other things. So, the user does not have to wait for the entire web page to refresh.
Typically, the interaction between the user and the server is synchronous. It includes the processes requiring a lot of user waiting. The user accesses the web application. Then, the request is processed by the server. The server sends data to the browser while the user waits. AJAX acts independently of web server software. When the user clicks on an Ajax-based application, the page shows what they are asking for without reloading the entire browser page. Ajax uses XHTML for content, CSS for presentation and JavaScript for displaying dynamic content.
One of the perfect examples of Ajax application is Google Maps. Google was the first to use web development technique "Ajax". Besides mapping applications, examples of AJAX apps are chats, e-mail applications, real-time searches, shopping cart apps, etc.
Building websites based on Ajax:
• XHTML and CSS browser-based presentation
• Interaction with the page through The DOM
• Data stored in XML and received from the server
• Data retrieval with XMLHttpRequest in the browser
• JavaScript
The most appealing benefit of Ajax is that it works within the browser and allows for the interaction with the application and the user to go independently of the interaction with the server. But, remember that AJAX applications will not work in web browsers that do not support JavaScript.
A mixture of web design and development techniques, AJAX has become an integral approach used in modern web development.