Using cookies, you can automatically log users
into your Web site when they load a page, or you can store temporary
information such as items in a shopping cart. Chris Cosentino walks you
through setting and deleting cookies in this article.
Setting Cookies with PHP
Using cookies, you can automatically
log users into your Web site when they load a page, or you can store
temporary information such as items in a shopping cart. Chris Cosentino
walks you through setting and deleting cookies in this article.
Cookies can be a very useful tool for your Web site. Cookies allow you to do
neat things, like automatically log a user into your site when he loads a page
in his browser, or store temporary information about your user, such as what
items he has in a shopping cart.
Cookies work by storing a small file on the user's browser. When the
user accesses a page on your site, your PHP script can check to see if any
cookies have been stored on the user's browser. Your script can detect only
cookies that you have stored. You won't be able to read cookies set by
other sites.
The information stored in these files are name-value pairs that PHP uses to
associate variable names with their values.
Setting a cookie is simple. You only need to enter the name of the variable
that you want to store and its value. The textbook definition of the
setcookie() function is:
setcookie( name, value, expiration );
It's important to note that you need to set your cookies before you send
any text to the browser. If you attempt to set the cookie after you send text to
the browser ( such as the <html> tag), an error appears, warning
that the cookie was not set.
The setcookie() function comes in two basic flavors:
Session Cookies: Cookies That Expire When the Browser Is Closed
Session cookies are stored on the user's browser until they close the
browser. Once the browser is closed, the cookie is erased.
To create a session cookie, you simply call the setcookie() function
in your script and provide it with a variable name and a value. You do not
provide it with an expiration time. Here's an example:
setcookie("username", "chris");
//equivalent to $username = chris
After the cookie is set, you can use the name of the cookie as a variable in
any page on your site. The variable is available up until the user closes the
browser.
The script cookie1.php is a simple script that asks a user for his first name
and then stores the first name to a cookie on the user's browser. The
cookie will remain there until the user closes the browser. Once the user
provides his first name from this page, the variable $f_name is
available from any PHP script on your site.
cookie1.php
Create the following script in a text editor and name it cookie1.php. This
script does two things. It asks the user for his first name and sets a cookie
that contains the user's first name, and it prints out a customized message
to the user if the cookie has already been set.
The first thing you need to do is determine whether you have the information
you need to store the cookie. In this example, you want to store the user's
first name, so you check to see if the $f_name variable is set. If the
$f_name variable is set (from the form that appears later in the
script), then you know that you can set the cookie to the value of
$f_name. If $f_name has not been set, then do
nothing:
<?
if(isset($f_name)) {
setcookie("f_name",$f_name);
}
?>
Next, you create a page as you normally would:
<html>
<head>
<title>The Cookie Script</title>
</head>
<body>
At this point in the script, you check to see (again) if the $f_name
variable has been set. If it has, then you print out a personalized message to
the user:
<?
if(isset($f_name)) {
?>
<h3>Welcome <? print $f_name ?>!
<?
If the $f_name variable has not been set, then you want to ask the
user for this information using a standard form:
} else {
?>
<form action="cookie1.php" method="POST">
Please tell us your first name: <input type="text" name="f_name">
<input type="submit" name="submit" value="Submit">
</form>
<?
}
?>
Finally, you end the page as you normally would:
</body>
</html>
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