PHP » Cookies and Sessions

This section describes some important functions available for tracking user sessions and setting cookies..

A cookie is a piece of information from the web server that is stored in the user's web browser. It can hold information available to the server throughout a visit and between visits to a web site. This section explains how to create cookies.

A session is the time during which a user is navigating through a web site. It is often useful to customize the information presented to the user based on, for example, the user's preferences. In order to do this, the web server must be able to identify the user. PHP provides functionality for automatically creating sessions and unique user IDs that can be used to store session variables, i.e. information specific to a user's current activities. Some important functions available for session tracking are explained in this section.