Java Platform, Enterprise Edition (Java EE) 8
The Java EE Tutorial
Early web applications were created mostly as static web pages. When a static web page is updated by a client, the entire page has to reload to reflect the update. In effect, every update needs a page reload to reflect the change. Repetitive page reloads can result in excessive network access and can impact application performance. Technologies such as Ajax were created to overcome these deficiencies.
The server response need not be in XML only; it can also be in other
formats, such as JSON (see Introduction to
http://www.json.org/). This tutorial does not focus on the
Ajax enables asynchronous and partial updating of web applications. Such functionality allows for highly responsive web pages that are rendered in near real time. Ajax-based web applications can access server and process information and can also retrieve data without interfering with the display and rendering of the current web page on a client (such as a browser).
Some of the advantages of using Ajax are as follows:
Form data validation in real time, eliminating the need to submit the form for verification
Enhanced functionality for web pages, such as user name and password prompts
Partial update of the web content, avoiding complete page reloads