Welcome to the JavaRanch, Abijeet!
CSS is best done as separate files referenced by the View Definitions (xhtml) that use them. JSF2 has some tags to make it fairly easy to do that.
JavaScript can be used by JSF views in pretty much the same way that it is in straight HTML, with one exception, and that is that when you attempt to locate a page element by its ID, the true (JavaScript/HTML) is a composite of the IDs of the "naming container" JSF components that contain it. When in doubt, use your browser's "show source" option to see the generated code. Any ID components that start with "j_" are probably automatically generated by an element that didn't have an explicit ID, and
you should hunt them down and put "real" IDs on those items, since the automatically-generated IDs are likely to change suddenly and unexpectedly.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.
