If you have been browsing the web for quite some time, then you might have come across cookies which allows your browser to remember passwords and other information that may have anything to do with your actions on a particular website. These can be preferences that would allow the browser or webpage on the browser to determine your habits online allowing it to perform the requested operations faster and easier. A cookie is called a client-based information for it is stored on the client computer (yours when you browse the web) and is taken or stored intact along with all the information it contains for a specified amount of time or till you delete your browsing history and cookies. If you have come across tracking cookies, these are information that defines you to a particular web page which is called upon on your next visit. When creating cookies with your page, there are specific parameters (cookies by the way are created using user-made code in PHP) that must be remembered so as not to fill up the hard disks of your client computers as they visit your website page again and again. The function setcookie is used with the following syntax:
setcookie(var1, var2, time)
The var 1 stands for the name of the cookie you are creating, with the var 2 containing the value of the said cookie and the last parameter is the time which specifies the amount of time it takes for the function to kill (terminate/delete) the cookie. A more defined and elaborate explanation of the function can be found on this page.