Detailed explanation of php cookie working principle and cookie examples

Detailed explanation of php cookie working principle and cookie examples_PHP tutorial

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Release： 2016-07-13 10:44:55

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In PHP, cookies are commonly used by us, but many friends may not know how cookies work. The following editor will sort out the working principle of PHP cookies and some examples of cookie reading and writing operations.

Cookies and session state

To do BS development, these two concepts are indispensable. Let’s have a general understanding first. Without practical application, it is difficult to go into depth. Please read the reference address in depth!
What are cookies?
A cookie is a small piece of text information that is passed between a web server and a browser along with user requests and pages. The information contained in the cookie can be read by the web application each time the user visits the site. Basics of How Cookies Work If a user returns to a page on the site and enters the URL www.*****.com, the browser looks for a cookie associated with that URL on their local hard drive. If the cookie exists, the browser sends it to your site with the page request.

What are cookies used for?
The most basic purpose is: Cookies can help Web sites save information about visitors. More generally, cookies are a way to maintain the continuity of a Web application (that is, to perform "state management"). It allows the Web site to remember you.

•When a customer visits a website based on PHP technology, the setcookie() function can be used in PHP to generate a cookie. After processing, the system sends the cookie to the client and saves it in the C:Documents andSettings username Cookies directory. Down.
• Cookies are part of the HTTP header, so the setcookie() function must be called before any content in the HTML itself is sent to the browser. This restriction is the same as the header() function (if you need to understand the head() function, please check it yourself).
•When the customer visits the website again, the browser will automatically send the cookie corresponding to the website in the C:DocumentsandSettings username Cookies directory to the server. The server will automatically convert the cookie passed from the client into a PHP variable. . In PHP5, cookies sent by the client will be converted into global variables. You can read it through $_COOKIE[‘xxx’].
Define a cookie
•Set cookies:
•Syntax: boolsetcookie(stringname,[stringvalue,[int expire,[stringpath,[stringdomain,[int secure]]]]]);
This cookie function can have 6 attributes, and the commonly used ones are 3 parameters.

1. Example:

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代码如下

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$value="the best way is by yourself";

setcookie("cookiename",$value,time()+60*60*24*7);

$value="the best way is by yourself";

setcookie("cookiename",$value,time()+60*60*24*7);

1. Receiving and processing cookies
PHP has good support for cookies. Just like form forms, PHP will automatically receive the HTTP header from the web server and process it when received. When receiving, use $_COOKIE["cookiename"] or $HTTP_COOKIE_VARS["cookiename"] (not recommended)

1. Note:
If the website has several different file directories and uses a cookie without a path, the cookie can only be accessed in the path of the file that sets the cookie. If a path is specified, the path when setting will be used as the specified path to access the cookie.

代码如下

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setcookie("CookieArray[0]","Value1");

setcookie("CookieArray[1]","Value2");

Create cookie array:

1. One:

The code is as follows

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代码如下

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setcookie("CookieArray['one']","Value1");

setcookie("CookieArray['two']","Value2");