Setting a cookie before page is refreshed/closed - php

Question

I'm once again asking for the SO community for a little help.
I'm modifying a Joomla "quiz" component to make it behave the way I need it to.
What I'm trying to do now is to change the "refresh" behavior of the component. Basically, every quiz has a timeout, i.e., a time when the quiz is no longer accessible to the user so when the timer gets to 0, the quiz is submitted and so on, but the default behavior of this component makes it that whenever the page is refreshed the timer will reset to the initial set time (let's say, 10 minutes)
The thing is I want to be able to have the timer continue from where it left of in case of a refresh.
I haven't used PHP since 3 or 4 years ago so I'm kinda lost.
To be able to achieve the desired behavior I'm setting up a cookie that will store (via implode) the initial time (when the quiz was opened) and the "now" time (on load it's set to 0 but upon refresh I want to "update" the cookie to store the reload time).
With the initial time and the now time, I'll be able to calculate how much time has passed and place the timer from where it left off.
The thing is, I'm trying to "update" the cookie with a javascript 'onbeforeunload' so that I can manage to get the refresh time into the cookie. But for some reason, it's not doing anything at all. When I go to see the cookie contents everything is still the same from when the cookie was set.
I know that in order to update the cookie I'll have to delete it and then set it again, but I'm being unsuccessful.
Heres the sample code:
//This is responsible for setting the cookie (via PHP):
<?php
$name = "progress";
$now = 0;
$time_diff = 0;
$expire = time() + 3600;
$data = array(time(), $now, $time_diff, $this->quiz->time_limit);
//$var = implode(',', $data);
if(isset($_COOKIE[$name])) {
/* If defined, update the timer */
} else {
setcookie($name, implode(',',$data), $expire);
}
echo $_COOKIE[$name];
echo "<br />";
echo $this->quiz->time_limit;
?>
And this is to detect the "refresh" event (with Javascript that will run PHP):
window.onbeforeunload = function() {
<?php
$name = "progress";
$list = explode($_COOKIE[$name]);
//delete cookie
setcookie($name, "", time() - 3600);
//Update the fields
$list['1'] = time(); //now - refresh time
$list['2'] = $list['1'] - $list['0']; //time_diff
//Set the cookie again
setcookie($name, implode(',', $list), time() + 3600);
?>
}
Can anyone point out what is wrong with this code?

Answer 1

As has been said in the comments, JavaScript cannot run PHP code like that... but if you use AJAX then you can. Now with the code you posted for us to see, if you load up your page in the browser and view the code your function will look like this:
window.onbeforeunload(){
}
So it's no surprise that nothing is happening with your cookies when you are closing your browser. Now, without seeing your other functions it's hard to tell exactly what is happening but you can use PHP and JavaScript intertwined but in a different fashion. Let me explain this with an example.
window.onbeforeunload(){
var name = <?php $name='Steve'; echo($name); ?>;
console.log(name);
}
If you had this code and loaded the page in the browser you would no longer see the PHP code, but instead would see this:
window.onbeforeunload(){
var name = 'Steve';
console.log(name);
}
With that being said, here are a few links you might find helpful.
JavaScript Cookies
Set/Get Cookie using PHP and JavaScript
Simple AJAX - PHP and JavaScript