title: How to implement Sessions in a Facebook Multi-pages canvas application (php sdk 4.0)
body: <p>Here is my question:
  Im trying to create a Facebook Canvas Application with PHP sdk 4.0 and im lost in all the confusing documentations...
  I don't understand how the login process is working with multiple pages application. Can someone help me please?</p>
  
  <p>I put this code on the landing page of the app and that works fine:</p>
  
  <pre><code>FacebookSession::setDefaultApplication( 'app_id', 'app_secret' );
  $helper = new FacebookCanvasLoginHelper();
  try {
      $session = $helper-&gt;getSession();
  } catch (FacebookRequestException $ex) {}
  </code></pre>
  
  <p>the question is: what should i do on the second page?
  _Write the same code?
  _Save the Facebook session in $_SESSION in order to use it on the other pages?
  _Save only the token to retreive the session?</p>
  
  <p>I walked the web for 2 days to find the answer with no result..
  I found Facebook documentation is not very clear</p>
  
  <p>Thx to you a lot!  ;)</p>