A Cookie can be defined as a thing that is used to store a
small amount of data (maximum around 4KB) within the user's browser itself. Later, whenever the
user revisits an already visited page, all the data in the cookie is automatically
sent to the server within the request.
A very common use of cookie is to store username and password on your computer
so that you don't have to login again each time you visit a website. We can make a cookie to last for
a fixed amount of time ranging between a few seconds to several years as per our desire. We can
even set a cookie to expire once the browser application is closed.
In the following example, setcookie() is used to store the number of pages user views in the his current
browser session. Here the expires argument is zero hence the cookie will disappear when the user
closes his browser. Further, the domain argument is an empty string meaning the browser will
only send the cookie back to the exact web server that created it.
Above example will display nothing in first run as $_COOKIE[ "yourViews" ] doesn ’ t
exist. But when the user reloads the page to run the script again, the code will display 1 ( true ) because
the browser has sent the yourViews cookie back to the server once hence second time the result will be:
Removing a Cookie
$t=time()-60; //this makes the time 60 seconds ago
setcookie( "visitor", "", $t);
echo "Cookie named visitor is no longer there";
This will produce following result
In order to remove the cookie, we use setcookie once again,
only set the expiration date to be sometime in the past (here 60 seconds).
This is done when you 'logout' of a site