PHP Cookies

In this tutorial, you will learn how to store a small amount of information inside the user's browser using PHP cookies.

What is a Cookie

A cookie is a small text file that allows you to store a small amount of data on the user's computer (up to4about KB (kilobytes). They are usually used to track information such as usernames, so that when the user visits the website again, the website can retrieve this information to display a specific personalized page.

Set Cookie

The setcookie() function is used to set cookies in PHP. Make sure to call the setcookie() function before any output is generated by the script, otherwise the cookie will not be set. The basic syntax of the function can be given as follows:

setcookie(name, value, expire, path, domain, secure);

The parameters of the setcookie() function have the following meanings:

Here is an example of creating a cookie named 'userName' using the setcookie() function and assigning it the value 'John Carter'. At the same time, the cookie expiration time is specified as30 days (}}30 days * 24 hours * 60 min * 60 sec).　 　 　 　

<?php
//Set Cookie
setcookie("username", "John Carter", time())+30*24*60*60);
?>

Access Cookie value

The PHP superglobal variable $_COOKIE is used to retrieve cookie values. It is typically an associative array containing a list of all cookie values sent by the browser in the current request, with cookie names as keys. You can access a single cookie value using standard array notation, for example, to display the username cookie set in the previous example, you can use the following code.

<?php
//Access a single Cookie value
echo $_COOKIE["username"];
?>

The PHP code in the above example produces the following output.

John Carter

It is best to check if the cookie is set before accessing the value of the cookie. For this purpose, you can use the PHP isset() function, as shown below:

<?php
//Verify if the cookie is set
if (isset($_COOKIE["username"])) {
　　　　echo "Hi " . $_COOKIE["username"];
} else {
　　　　echo "Welcome Guest!";
}
?>

You can use the print_r() function like print_r($_cookie) to view the structure of the $_cookie associative array, just like you would handle other arrays.

Delete Cookie

You can delete a cookie by calling the same setcookie() function with the cookie name and any value (such as an empty string), but you need to set it to an expiration date before now, as shown in the following example:

<?php
//Delete cookie
setcookie("username", "", time())-3600);
?>