The core idea behind AJAX is to make the communication with the server asynchronous, so that data is transferred and processed in the background. As a result the user can continue working on the other parts of the page without interruption. In an AJAX-enabled application only the relevant page elements are updated and only when necessary.In contrast, the traditional synchronous (postback-based) communication requires a full page reload each time data is transferred to/from the server. This leads to the following negative effects:
Poor Interactivity - the user interaction with the application is interrupted by a postback every time a server call is needed.
Ineffectiveness - the full page is rendered and transferred to the client on each postback. This process is time consuming and traffic intensive.
Low Usability - the requirement for full page postback whenever the user interface is changed imposes hefty limitations on the degree of sophistication a web user interface can achieve. Before AJAX, rich and smooth interfaces with on-demand updates could only be implemented using Flash technology.
Below is a diagram of the complete lifecycle of an AJAX-enabled web form.
Initial request by the browser – the user requests a particular URL
The server processes the request and sends a response in XML format to the client (XML document). It contains the data only of the page elements that need to be changed. In most cases this data comprises just a fraction of the total page markup
The AJAX engine processes the server response, updates the relevant page content or performs another operation with the new data received from the server. (HTML + CSS)
AJAX development however is a quite complex process. It requires:
Comprehensive knowledge of the ASP.NET page lifecycle - AJAX applications typically break the normal page life-cycle and do not work properly. As a result developers have to handle ViewState management, EventValidation, and preservation of client-scripts
The Telerik RadAjax framework eliminates those challenges. The product features Telerik Click-and-Go™ patent-pending technology, which allow you to jump-start your AJAX development today:
AJAX-enable any existing or new application, regardless of its level of complexity
You don't need detailed knowledge of AJAX
You don't have to modify your application - you do not need to place Update Panels, set triggers, manually invoke AJAX requests, etc.