Using Cookies in PHP

A cookie is a message given to a Web browser by a Web server. The browser stores the message in a small text file that the server embeds on the user's computer. Each time the same computer requests a page with a browser, the cookie is sent back to the server too.
There are a wide variety of things you can do with cookies. They are used to store information about user, visited pages, poll results and etc. The main purpose of cookies is to identify users and possibly prepare customized Web pages for them.
How to Create a Cookie?
How to Retrieve a Cookie Data?
How to Delete a Cookie?
Normally cookies are used only to store small amounts of data. Websites can read the values from the cookies and use the information as desired. In addition to the information it stores, each cookie has a set of attributes that helps ensure the browser sends the correct cookie when a request to a server is made.
Even though cookies are not harmful some people do not permit cookies due to concerns about their privacy. In this case you have to use Sessions.