I'm passing a variable to another page in a url using sessions like this but it seems that I can't concatenate another variable to the same url and retrieve it in the next page successfully
Page 1
session_start();
$event_id = $_SESSION['event_id'];
echo $event_id;
$url = "http://localhost/main.php?email=" . $email_address . $event_id;
Page 2
if (isset($_GET['event_id'])) {
$event_id = $_GET['event_id'];}
echo $event_id;
echo $event_id shows an error Undefined variable on page 2 but if I use just the event_id in the $url like here
$url = "http://localhost/main.php?event_id=" . $event_id;
That works fine, but I need to be able to use both variables in the url so that page 2 can retrieve get them.