Count Start Over On Page Refresh?

I found a script that puts a JavaScript countdown timer on a web page. The timer uses a PHP session so the timer does not reset until it reaches zero even if the user refreshes the page or leaves and comes back. When the timer reaches zero, the user is redirected to a different page.

The problem I have is when the user goes back to the timer page, after the redirect, the timer is still at zero and the user is immediately redirected again.

The timer does not restart until the user accesses the page for a second time.

If the redirect function is removed and you let the countdown go to zero, the page has to be refreshed twice to restart the countdown. I don't know if this is a PHP or JavaScript issue.

Can this be fixed so the countdown resets as soon as the user revisits the page after the redirect?

PHP Code:

<?php
session_start();
if (!isset($_SESSION['endOfTimer'])){
$endOfTimer = time() + 10;

[Code]....