Hello Reader! If you developing the website for a global purpose then getting the time zone of your user is a important factor.
In the example below we'll see how to get the user's time zone by using JavaScript and PHP with a custom webpage.

First get the jquery file (The latest one) and call it on header <script type="text/javascript" src="http://code.jquery.com/jquery-latest.min.js"></script>

Now write this is custom Jquery just below it:-

<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://abc.com/date.php",
                data: 'time='+ visitortimezone,
                success: function(){
                    location.reload();
                }
            });
        }
    });
</script>

Where abc.com is your website and date.php is our next page

Now the last step is to create date.php in the location as in url above

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

Now it will return the user's timezone.