How to pass a javascript variable to PHP without using $_GET?

Question

So im trying to set the php timezone through javascript, so users automatically have the time set properly to their timezome. Now i found this code online, but unfortunately it transfers the determined value of the javascript through a GET value. Is there a way i can use this, but not require the inclusion of the GET value in the URL? as this happens to break my website due to how the .htaccess ReWriterules are set.

Here is the code for the timezone. What i need is a way to transfer the determined offset value from the javascript to the php without using the GET in the url. Is this possible?

<?php
session_start();
if(!isset($_SESSION['timezone']))
{
    if(!isset($_REQUEST['offset']))
    {
    ?>
    <script>
    var d = new Date()
    var offset= -d.getTimezoneOffset()/60;
    location.href = "<?php echo $_SERVER['PHP_SELF']; ?>?offset="+offset;
    </script>
    <?php    
    }
    else
    {
        $zonelist = array('Kwajalein' => -12.00, 'Pacific/Midway' => -11.00, 'Pacific/Honolulu' => -10.00, 'America/Anchorage' => -9.00, 'America/Los_Angeles' => -8.00, 'America/Denver' => -7.00, 'America/Tegucigalpa' => -6.00, 'America/New_York' => -5.00, 'America/Caracas' => -4.30, 'America/Halifax' => -4.00, 'America/St_Johns' => -3.30, 'America/Argentina/Buenos_Aires' => -3.00, 'America/Sao_Paulo' => -3.00, 'Atlantic/South_Georgia' => -2.00, 'Atlantic/Azores' => -1.00, 'Europe/Dublin' => 0, 'Europe/Belgrade' => 1.00, 'Europe/Minsk' => 2.00, 'Asia/Kuwait' => 3.00, 'Asia/Tehran' => 3.30, 'Asia/Muscat' => 4.00, 'Asia/Yekaterinburg' => 5.00, 'Asia/Kolkata' => 5.30, 'Asia/Katmandu' => 5.45, 'Asia/Dhaka' => 6.00, 'Asia/Rangoon' => 6.30, 'Asia/Krasnoyarsk' => 7.00, 'Asia/Brunei' => 8.00, 'Asia/Seoul' => 9.00, 'Australia/Darwin' => 9.30, 'Australia/Canberra' => 10.00, 'Asia/Magadan' => 11.00, 'Pacific/Fiji' => 12.00,  'Pacific/Tongatapu' => 13.00);
        $index = array_keys($zonelist, $_GET['offset']);
        $_SESSION['timezone'] = $index[0];
    }
}
date_default_timezone_set($_SESSION['timezone']);

I have been told this may be possible with JSON, but after reading online im unable to understand the notation to properly use this.

Answer 1

If you don't want to use a GET request, you could consider using a POST request instead. You can send the data from with an Ajax request in JavaScript. Using jQuery, this would look something like:

$.ajax({
   'url': 'PATH_TO_PHP_SCRIPT',
   'type': 'POST',
   'data': 'timezone=' + timezoneVariable
});

Answer 2

If you don't want to use JSON and ajax(XMLHttpRequest), you can use cookies. Since both javascript and php can read these, create one using javascript to store the timezone . Then in your php code read that cookie.

to create a cookie in javascript use :

document.cookie = 
    'myName=' + value + 
    '; expires=' + now.toGMTString() + 
    '; path=/';

and to read it in your php :

$_COOKIE['myName']

Answer 3

You can simply GET/POST an URL like /tz/TIME_ZONE where TIME_ZONE is whatever timezone you want to set.