JavaServer Faces (JSF) is a Java web application framework intended to simplify development integration of web-based user interfaces. It is a standardized display technology, which was formalized in a specification through the Java Community Process. It utilizes server-side components to create views, handle user input, and orchestrate application flow.
One of the main goals of JSF is to encapsulate various client-side technologies (like JavaScript, HTML and CSS) so that JSF developers don’t have to write JS or CSS unless they really want to.
However, when it is necessary to integrate JavaScript with JSF, it can be achieved by using JavaScript to call server-side managed beans, or use JavaScript to manipulate the HTML DOM that is generated by the JSF components.
For instance, AJAX (Asynchronous JavaScript and XML) technology may be employed within JSF to facilitate asynchronous communication between the client and server. Ajax requests are initiated at the client side using JavaScript, then JSF lifecycle is used at the server side to process the Ajax request, and finally JavaScript is used at the client end once again to update the user interface as a result of the Ajax response.
Also, PrimeFaces, a lightweight open source component suite for JSF, provides a JavaScript API, allowing for the integration of JavaScript into JSF in a more seamless way.
On the other hand, JSF 2.0 onwards comes with built-in Ajax support, which means there’s less requirement for direct manipulation of JavaScript, as much of this can be handled declaratively within the XHTML pages.
