"Layouts provide a structure for the creation and
serving of portal pages. Layouts aggregate all of the content
generated by the portlet, based on region and order, merge them
with some additional content provided by the portal, and serve a
response back to the user. By providing support for AJAX in the
layout, helps facilitate the easy development and implementation of
dynamic functionality in pages, with minimal effort.
"Layout markup is implemented using JSP tags. The JBoss JSP tag
library, portlet-layout.tld, offers tags that facilitate the
implementation of AJAX features in layouts. A JSP layout can be
changed to an AJAX-supported page simply by adding references to
the tags. Hence, using tags also helps with the easy implementation
"The following is the layout page from the default portal
and shows AJAX support implemented as tags:"