title: php, admin and user login from same browser causing session variable to be changed unwantedly
body: <p>Both admin and users can log in. After logging in they can browse same pages.</p>
  
  <p>There are options for admin and users to insert, edit and delete items.</p>
  
  <p>Admin can do all those 3 tasks for any items created by anyone. But a user can perform those tasks only  for the items created by him/herself. So tracking is there in database AS TO  who created a particular item.</p>
  
  <p><code>$_SESSION['admin_user']</code> is assigned 1 if it is the admin or 2 otherwise. This session variable decides whether the page is intended for the admin or any other user.</p>
  
  <p>But if the admin logs in and then another user also logs in from the same browser then the session variable gets the latter value. </p>
  
  <p>For whatever reason, let use assume that such scenario for the admin and user to log into the same browser at the same time can take place.</p>
  
  <p>How to make it possible that even if those two different type of users enter the site in the mentioned way, both of them will get their corresponding pages (i.e. when admin clicks on a menu link s/he will get the expected page and the same will be true for any user from the same browser at the same time)?</p>