使用PHP会话进行页面导航

Question

I am trying to make simple navigation rules for a visitor for my website. I want to prevent visitor accessing specific pages if they have not visited other pages before. I have this simple code on page1.php:

<?php 
 session_start();
 $_SESSION["currentPage"] = 1;
?>

And this code on my page2.php:

<?php
 session_start();
 if ($_SESSION["currentPage"] == 1 ) {
   $_SESSION["currentPage"] = 2;
   $_SESSION["test"] = "Hello";
 }else{ 
   $_SESSION["currentPage"] = 3;
  }
?>

After visiting page1.php and then page2.php and echoing out $_SESSION["currentPage"] and $_SESSION["test"] I get "Hello" and "3".

I just don't understand why the code is executed in both blocks of the if statement...I need it to stop after $_SESSION["currentPage"] is set to "2".

I am running PHP 5.3.28

Answer 1

It executes

$_SESSION["currentPage"] = 2;
$_SESSION["test"] = "Hello";

When you open page2.php first time, and

$_SESSION["currentPage"] = 3;

When you refresh the page because $_SESSION["currentPage"] is not 1 anymore.
$_SESSION is persistent across request. Clear cookies to and try again.