Parameters and variables let you share page data in different ways. Basically you define page parameters for information that will be passed to your page; you define page variables to contain values internal to the page.
A page parameter is a named value that you can pass from one page to another. Usually a page parameter is appended to a URL as a query string or is submitted with a form. After the value is passed from a page, a server script can access the value and use it as needed in generating the target page.
A page variable is a temporary value that can be saved and made accessible to other pages, including the page where the variable is set. A page variable is available as long as a page is active.
A session variable is like a page variable, but with a longer life-span. A session variable is available for the length of the user’s browser session. You use a session variable to make the user’s information available to many pages.
Variables and login data Variables, either page or session, can be used to store login information for a user’s site visit. This lets that person visit a number of pages without needing to log in again.
4GL JSP pages give you a straightforward way to define and keep track of parameters and variables during development. The 4GL extensions to the Web Target object model manage the parameters and variables when the page is processed by a JSP server.
For information about 4GL JSP pages, see Chapter 9, “Developing 4GL JSP Pages.” For information on referring to parameters and variables in scripts on 4GL JSP pages, see “Adding scripts to 4GL JSP pages”.
