PHP How to completely destroy a session after leave the page - php

Question

I want to make a simple PHP page where you can only access if you log in first. My code is something like this:
if (the user logged in correctly) {
session_start();
echo "THE HTML PAGE. (I did this in echo because I only want to show it for the logged in users.)";
} else {
header ("Location: index.html");
die();
session_destroy();
}
So my goal is that, when the user click onto the "Go back on page" button, the session gets destroyed, and only start a new after logged in. But now, if the user click onto the "Go back on page" button, than click onto the "Go forward on page" button. it says, Document Exired. It's cool, but if I refresh the page, I can access the page without login.

Answer 1

Here is a solution
// put on top of every page
session_start();
function is_logged_in(): bool
{
if (isset($_SESSION['email']) && isset($_SESSION['id']) && isset($_SESSION['is_logged_in'])) {
return true;
} else {
return false;
}
}
function is_auth()
{
if (!is_logged_in()) {
session_destroy(); // change happend here
header("Location: index.html");
die();
}
}
is_auth();
// add your code here

Answer 2

if(isset($_SESSION['email']) && isset($_SESSION['id']))
{
return true;
}
else
{
return false;
}
// and then call this function in header file to check.

Answer 3

header ("Location: index.html");
die();
session_destroy();
Regarding session destruction, you cannot do it that way. See below:
First you need to destroy the session.
Then you need to redirect the user.
Correct:
session_destroy();
header ("Location: index.html");
die();

Answer 4

sometimes unset function also works see unset and destroy are two seprate function,
unset is useful for unsetting the some values like email,id,name etc and destroy completely destroys session, so make sure destroying the session you again not need the session so try to use unset().