<%@ taglib prefix="s" uri="/struts-tags"%>
<table> <tr><td colspan="2"> <s:if test='%{#session.PERSON != null}'> <s:button value="LogOff" action="LogoffAction"> </s:button> </s:if> <s:else if test='%{#session.PERSON ==null}'> <s:button value="Login" action="LoginAction"> </s:button> </s:else if> </td></tr> </table> but when test, in the logfile, giving the error SEVERE: Servlet.service() for servlet jsp threw exception org.apache.jasper.JasperException: /PageMenu.jsp (line: 7, column: 5) No tag "button" defined in tag library imported with prefix "s" at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:42) at org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:408) at org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:199) at org.apache.jasper.compiler.Parser.parseCustomTag(Parser.java:1215) i check the reference, s:button is valid, if so, why not receive the error at above please advise john