How to make page require a session variable?

[iStudent]

How to make page require a session variable?

[jaswinder_rana]

say you wanna check if $_SESSION['userid'] does not exist then stop or redirect

if(!isset($_SESSION['userid']) || (isset($_SESSIOn['userid'] && empty($_SESSION['userid']))
{
  exit;//if you wanna stop loading page
  header('Location: otherpage.php');//redirect the page
} 

first condition checks if the variable is set and second checks if variable set then is it empty?

hope it helps you.