thanks pete.muir at jboss.org. i found a4j:jsFunction is useful,, i call a generated a4j:jsFunction javaScript from extjs View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4104516#4104516 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4104516