if(userName==null){
response.sendRedirect("error1.jsp");
}
else{
if(!userName.equals("admin")){
response.sendRedirect("error.jsp");
}
}
<IFRAME border=1
name=guest marginWidth=0 frameSpacing=0 marginHeight=0
src="user_logrefresh.jsp" frameBorder=0 noResize width=100
scrolling=no height=20 vspale="100"> </IFRAME></td>