在JSP中使用JavaScript进行会话检查

Question

I have done session activation and deactivation using servlets using

HttpSession s = request.getSession(); 
s.setAttribute("uname", uname);

and deactivation in logout servlet using

HttpSession sess=  request.getSession();
sess.invalidate();

Now I want to check in my JSP page that is session is activate or not?
So for this I want this checking using JavaScript . I have method to check this using simple JSP code but I want this using JavaScript's function. So that if session is activate then I will reload same page and if session is expired then it will redirect to the login.jsp page. So I could not get any idea about it.

Answer 1

As for tomcat webservers the session is usually mantained by a cookie with name JSESSIONID. However from that cookie being set you can not be sure that the session is still valid. The only one who can tell you, having a valid session or not is the server. So it'll be better to do the redirect on the server.