JSF supports Ajax by using a built-in JavaScript resource library that is provided as part of the JavaServer Faces core libraries. This built-in Ajax resource can be used in JavaServer Faces web applications in one of the following ways:

• By using the f:ajax tag along with another standard component in a Facelets application. This method adds Ajax functionality to any UI component without additional coding and configuration.
• By using the JavaScript API method jsf.ajax.request() directly within the Facelets application. This method provides direct access to Ajax methods, and allows customized control of component behavior.

The f:ajax tag is a JSF core tag that provides Ajax functionality to any regular UI component when used in conjunction with that component. In the following example, Ajax behavior is added to an input component by including the f:ajax core tag:

<h:inputText value="#{bean.message}">

 <f:ajax />

</h:inputText>