Overview

The classic JADE Web application framework centered all activity on a client-server round-trip architecture with a Web service architecture. Under this system all processing is done on the server, and the client is only used to display static HTML content. The biggest drawback with this approach is that all interaction with the application must pass through the server; that is, data is sent to the server, the server responds, and a full page refresh occurs on the client with the response, when only a small part of the display requires updating.

By using a client-side technology that can execute instructions on the client’s computer, Rich Internet Applications (RIAs) can circumvent this slow and synchronous loop for many user interactions and perform partial page updates.

The main characteristic of an RIA is that it has an intermediate layer of code, often called a client engine, between the user and the server. This client engine is usually downloaded at the beginning of the application, and can be supplemented by further code downloads as the application progresses. The client engine acts as an extension of the Web browser, and usually takes over responsibility for rendering the user interface and for server communication.

In a RIA, it is not uncommon for a large number of messages to be sent between a browser client and the server, but the size of each message is typically small. An example of the way this strategy works would be a user completing address and phone number details on a form in a Web browser. When the user tabs out of the phone number field, a message can be generated to validate the number that was entered. The message is sent to the appropriate JADE Web service method and the response is sent back to the browser. The browser client processes the response and takes any action that is necessary.

The JADE Rich Internet Application framework uses the JavaScript language. It is a client-side language that can run code and is installed on most Web browsers. JavaScript code is used to facilitate the messaging and event handling and the JADE Web service framework is the client-server communication link in this Rich Internet Application strategy.

The browser client, by executing JavaScript, manipulates the displayed page with incremental updates avoiding the traditional full page refreshes.