How to Ascertain a Client's Time Zone

Determining the time zone of a client can be a valuable asset for various applications. This article examines the available methods to retrieve a client's time zone, with a particular emphasis on the PHP Zend Framework.

One common approach involves using JavaScript to obtain the local time and redirect to the server with the information. However, this can be cumbersome and may introduce security concerns.

Leveraging jQuery and PHP

A more robust solution utilizes both jQuery and PHP to accomplish the task:

1. PHP Code:

   • Implement a session_start() and retrieve the time zone from the session variable, if present.

2. jQuery Code:

   • Include jQuery and check if the session variable is empty.
   • If empty, obtain the browser's local time using new Date() and calculate its offset from GMT.
   • Perform an AJAX request to a PHP script (e.g., timezone.php) with the offset information.
   • Upon successful completion, reload the page.

3. Timezone.php:

   • In the timezone.php script, start a PHP session and store the time zone value in the session variable.

4. Redirect and Session Reading:

   • The initial page load prompts the jQuery script to retrieve the time zone and create a session if it does not already exist.
   • Subsequent page loads will have access to the stored time zone information in the session variable.

This method not only provides the client's time zone offset in seconds but also allows you to store and retrieve it across multiple page views. By utilizing a combination of JavaScript and PHP, you can obtain the client's time zone both accurately and securely.