Guessing User's TimeZone in PHP

Question

As of PHP5.3 (I think) it became a requirement for the date.timezone to be set in the php.ini file, or to be set at runtime via the date_default_ti

Answer 1

I'd probably use the date_default_timezone_get() function:

string date_default_timezone_get  ( void  )

In order of preference, this function returns the default timezone by:

• Reading the timezone set using the date_default_timezone_set() function (if any)
• Reading the TZ environment variable (if non empty) (Prior to PHP 5.3.0)
• Reading the value of the date.timezone ini option (if set)
• Querying the host operating system (if supported and allowed by the OS)

http://www.php.net/manual/en/function.date-default-timezone-get.php

Answer 2

Mike's approach only gets you the web server's time zone. I believe you are trying to get the user's time zone. I wrote a function using jQuery and PHP. This is tested, and does work!

On the PHP page where you are want to have the timezone as a variable, have this snippet of code somewhere near the top of the page:

<?php    
    session_start();
    $timezone = $_SESSION['time'];
?>

This will read the session variable "time", which we are now about to create.

On the same page, in the , you need to first of all include jQuery:

<script type="text/javascript" src="http://code.jquery.com/jquery-latest.min.js"></script>

Also in the , below the jQuery, paste this:

<script type="text/javascript">
    $(document).ready(function() {
        if("<?php echo $timezone; ?>".length==0){
            var visitortime = new Date();
            var visitortimezone = "GMT " + -visitortime.getTimezoneOffset()/60;
            $.ajax({
                type: "GET",
                url: "http://domain.com/timezone.php",
                data: 'time='+ visitortimezone,
                success: function(){
                    location.reload();
                }
            });
        }
    });
</script>

You may or may not have noticed, but you need to change the url to your actual domain.

One last thing. You are probably wondering what the heck timezone.php is. Well, it is simply this: (create a new file called timezone.php and point to it with the above url)

<?php
    session_start();
    $_SESSION['time'] = $_GET['time'];
?>

If this works correctly, it will first load the page, execute the JavaScript, and reload the page. You will then be able to read the $timezone variable and use it to your pleasure! It returns the current UTC/GMT time zone offset (GMT -7) or whatever timezone you are in.

Cheers

</Westy92>