Working with sessions in PHP is very basic. You can pass values to session as key/value pairs. To store and receive data from sessions are very easy to use.

Sessions can store user information, heres how to use them

One of the first stumbling blocks new developers encounter when trying to build a shopping cart application is dealing with sessions and user ID's. Using the full date with the visitor's ip address an Id that is not only unique, but also descriptive can be generated. Once created, the user Id maintains session information for the client and is inserted into the database for storage.

Whenever you want to create a website that allows you to store and display information about a user, determine which user groups a person belongs to, utilize permissions on your website or you just want to do something cool on your site, PHP's Sessions are vital to each of these features. You may be thinking right now, well that's nice, but I can do this with Cookies! This may come to you as a suprise, but Cookies are about 30% unreliable right now and it's getting worse every day. More and more web browsers are starting to come with security and privacy settings and people browsing the net these days are starting to frown upon Cookies because they store information on their local computer that they do not want stored there. PHP has a great set of functions that can achieve the same results of Cookies and more without storing information on the user's computer. PHP Sessions store the information on the web server in a location that you chose in special files. These files are connected to the user's web browser via the server and a special ID called a "Session ID". This is nearly 99% flawless in operation and it is virtually invisible to the user.

we're going to show you how you can make use of php sessions easily and quickly. we assume that you are familiar with the basics of php. the php session page and function list can be found here. you should have register globals switched off in your php configuration and for sessions not to use cookies. you can do this by editing php.ini

Learn how to add and play around with cookies. Setting and playing around with cookies is a fun and useful way to save data on a user's hard drive, and can successfully store valuable information which may be helpful the next time they come to the site. Its fairly simple to set up, and even easier to read.

Lean all about Flash Cookies and how to make great use of them in PHP

Well most of your php.ini files are set up to cancel your sessions after 3 hours or 180 minutes, but in some instances this may not work, or maybe you need the session to be cancelled sooner than 3 hours. This type of system is used by banks all the time. If you have online banking you can relate to what I am talking about. Basically what I am trying to say is let's say you want the end user to be logged out after 10 minutes of inactivity after they login. You will need to write a custom script to achieve this. Everyone could use this tutorial, even if you think you will never need a custom timeout session, a little extra knowledge never hurt anyone. But seriously anyone who writes membership systems in PHP could potentially use this system. It is a very easy system to adapt to your code.

Cookies in PHP are stored in the environmental variable HTTP_COOKIE_VARS array. The names of the set cookies will be the actual variable names, not the HTTP_COOKIE_VARS itself, since that is an array. The cookies are stored in name-value pairs. Something to remember about setting cookies. You can't have an HTML tag before setting any cookies, so set your cookies before escaping PHP to set the HTML tags and printing anything to the browser. That is a limitation from browsers and an easy mistake to make.

Cookies are a great invention, allowing the web developer to maintain the login status of their users. However, problems occur when your site or network has more than one domain. The cookie specification says that any cookie set for one domain, must not be sent to any other domain. Therefore, if you set a cookie in your user's browser on one domain, that cookie will not be available on any other domain. This is a big problem, if you want your users to log in on one of your sites and still be logged in on your other domains.