An element type indicates the name and type of such variables although details on the name 
of the variable may depend on the Scripting Language. The scripting language may also 
affect how different features of the object are exposed; for example, in the JavaBeans 
specification, properties are exposed via 
 methods, while these are available 
directly in the JavaScript
programming language.
The exact rules for the visibility of the variables are scripting language specific. Chapter 4 
defines the rules for when the 
 attribute of the 
 directive is  java .
Scripts, Actions, and Beans
Scripting elements, actions and Beans are all mechanisms that can be used to describe 
dynamic behavior in JSP pages. Different authors and authoring tools can use these 
mechanisms in different ways based on their needs and their preferences. The JSP 
specification does not restrict their use but this section provides some guidelines that may be 
useful to understand their relative strengths.
Beans are a well known and well supported component framework for the Java platform that 
can be accessed easily from the Java programming language and other JSP page scripting 
languages. Some JSP page authors, or their support organizations, may create or reuse Bean 
components to use from their JSP pages.
Actions provide an abstraction that can be used to easily encapsulate common actions. 
Actions typically create and / or act on (server side) objects, often Beans.
The JSP specification provides some standard actions that can be used to interact with any 
Bean. If the Bean is extended so it implements the 
 interface, then the Bean becomes a 
tag handler and it can be used directly in the JSP page with improved integration into the 
template data.
Scripting elements are very flexible; that is their power but also their danger as they can 
make hard understanding and maintain a page that uses them extensively; they may also 
make it hard for an authoring tool. In some development contexts, JSP pages will mostly 
contain only actions (standard or custom) with scripting elements only used as a  gluing  
mechanism that can be used to  fill in  the actions that are described using actions (and 
Beans and EJB components). In other development contexts JSP pages may contain 
significant amounts of scripting elements.
The JSP specification is designed to support the dynamic creation of several types of 
structured documents, especially those using HTML and XML.
JavaServer Pages 1.1 Specification   November 30, 1999

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