they can be used to react to session and request level lifecycle events, such as when an attribute is added to the session, or removed from the session. In tags I guess this would translate to changing the behavior of a tag according to whether an attribute has been successfully been added to the request or session level. I havent seen anyone use these to date
chanoch<p><a href="http://www.amazon.com/exec/obidos/ASIN/1861007736/" target="_blank" rel="nofollow">Author of Professional Apache Tomcat</a></p>
The <listener> element in the JSP 1.2 TLD is useful for registering a Servlet 2.3-style listener on whose behavior a taglib depends. As an example, a tag library might want to ensure that certain values are initialized before running.
Shawn Bayern<br />"JSTL in Action" <a href="http://www.jstlbook.com" target="_blank" rel="nofollow">http://www.jstlbook.com</a>