The "input" tag extension library lets you present HTML <form>
elements that are tied to the ServletRequest that caused the
current JSP page to run. That is, using this library, you can
easily prepopulate form elements with prior values that the user
has chosen -- or with default values for the first time a user
hits a web page. This is useful when you need to present the
same page to the user several times (e.g., for server-side validation).