i want to share something with a specific group of people.
the way i want to do it is: before the page is loaded , i prompt a question to the viewer , if the answer is right , then the page is loaded, if the answer is wrong , the user is turn to the warning page.(i want to avoid the registration process, a specific question is ok)
but there is a problem with this : every time the page is reloaded , the user have to type the answer again?
is there anyway that i can avoid this ?
(I assume you don't know how sessions work because you look new to StackOverflow) No, PHP (or other modern server technologies like ASP) have a session system that allows multiple users be online at same time. The server stores session variables in files, one per user. See http://ca2.php.net/manual/en/intro.session.php
First, I wouldn't recommend your approach for anything more than a trivial scenario. That being said, you would want to write a page that serves as your security page. On postback, validate the answer, set a session variable, and redirect to the protected page. The protected page should do a check during its load on that same session variable and redirect to the security page if the user has not answered the security question.
You might also be interested in using Apache's .htaccess files to control access: http://httpd.apache.org/docs/2.0/howto/auth.html
(for questions about using .htaccess, check ServerFault)