A JSP contains static template text that is written to the output stream. It also contains dynamic content that can take several forms:
Directives provide global information for the page, or include a file of text or code.
Scripting elements (declarations, scriptlets, and expressions) manipulate objects and perform computations.
Standard tags, or actions, perform common actions such as instantiating a JavaBeans component or getting or setting its properties, downloading a plug-in, or forwarding a request.
Custom tags perform additional actions defined in a custom tag library.
“JSP page authoring” provides a brief description of each of these types of dynamic content. For more detailed information, see the JavaServer Pages, or one of the many books about JavaServer Pages technology.