setcookie() — Send a cookie

Syntax : bool setcookie ( string $name [, string $value [, int $expire [, string $path [, string $domain [, bool $secure [, bool $httponly ]]]]]] )

setcookie() defines a cookie to be sent along with the rest of the HTTP headers. Like other headers, cookies must be sent before any output from your script (this is a protocol restriction). This requires that you place calls to this function prior to any output, including and tags as well as any whitespace.

Once the cookies have been set, they can be accessed on the next page load with the $_COOKIE or $HTTP_COOKIE_VARS arrays
Parameters :

name : The name of the cookie.

Value : The value of the cookie. This value is stored on the clients computer; do not store sensitive information. Assuming the name is ‘cookiename’, this value is retrieved through $_COOKIE['cookiename']

expire :The time the cookie expires.

This is a Unix timestamp so is in number of seconds since the epoch. In other words, you’ll most likely set this with the time() function plus the number of seconds before you want it to expire. Or you might use mktime(). time()+60*60*24*30 will set the cookie to expire in 30 days. If set to 0, or omitted, the cookie will expire at the end of the session (when the browser closes).

Note: You may notice the expire parameter takes on a Unix timestamp, as opposed to the date format Wdy, DD-Mon-YYYY HH:MM:SS GMT, this is because PHP does this conversion internally.
expire is compared to the client’s time which can differ from server’s time.

Path : The path on the server in which the cookie will be available on. If set to ‘/’, the cookie will be available within the entire domain . If set to ‘/foo/’, the cookie will only be available within the /foo/ directory and all sub-directories such as /foo/bar/ of domain . The default value is the current directory that the cookie is being set in.

domain : The domain that the cookie is available. To make the cookie available on all subdomains of example.com then you’d set it to ‘.example.com’. The . is not required but makes it compatible with more browsers. Setting it to www.example.com will make the cookie only available in the www subdomain. Refer to tail matching in the » spec for details.

Secure : Indicates that the cookie should only be transmitted over a secure HTTPS connection from the client. When set to TRUE, the cookie will only be set if a secure connection exists. The default is FALSE. On the server-side, it’s on the programmer to send this kind of cookie only on secure connection (e.g. with respect to $_SERVER["HTTPS"]).

Httponly : When TRUE the cookie will be made accessible only through the HTTP protocol. This means that the cookie won’t be accessible by scripting languages, such as JavaScript. This setting can effectly help to reduce identity theft through XSS attacks (although it is not supported by all browsers). Added in PHP 5.2.0. TRUE or FALSE

Return Values :

If output exists prior to calling this function, setcookie() will fail and return FALSE. If setcookie() successfully runs, it will return TRUE. This does not indicate whether the user accepted the cookie.

Examples :

<?php
	//Calculate 60 days in the future
	//seconds * minutes * hours * days + current time
	$inTwoMonths = 60 * 60 * 24 * 60 + time();
	setcookie('lastVisit', date("G:i - m/d/y"), $inTwoMonths);
?>

Retrieving Your Fresh Cookie

<?php
	if(isset($_COOKIE['lastVisit']))
        $visit = $_COOKIE['lastVisit'];
	else
        echo "You've got some stale cookies!";

	echo "Your last visit was - ". $visit;
	?>

Display:
Your last visit was – 12:40 – 03/20/10