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What are PHP cookies? How to create? How to delete it?
- 慕斯Original
- 2021-05-28 10:22:042409browse
The previous article introduced you to "Those "things" about PHP files! ! ! 》, this article continues to introduce to you what is PHP Cookie? How to create? How to delete it?
Hope it’s helpful to you!
What are Cookies?
Cookies are often used to identify users. A cookie is a small file that a server leaves on a user's computer. Each time the same computer requests a page through the browser, the cookie will be sent to the computer. With PHP, users can create and retrieve cookie values.
How to create a cookie?
setcookie() function is used to set cookies.
Note: setcookie() function must be located before the tag.
Syntax:
setcookie(name, value, expire, path, domain);
PHPsetcookie() parameter details:
As shown in the figure:
Regarding the creation of cookies, we use code to show it specifically:
Example 1:
First create a cookie named "user" and then assign a value "PHP" and also specifies that this cookie will expire in one hour.
The code is as follows:
<?php
setcookie("user","php",time()+3600);
//在发送 cookie 时，cookie 的值会自动进行 URL 编码，在取回时进行自动解码。
//为防止 URL 编码，请使用 setrawcookie() 取而代之。
?>
方法二：用户还可以通过另一种方式设置cookie的过期时间，代码如下：
<?php
//示例1
//setcookie("user","php",time()+3600);
//在发送 cookie 时，cookie 的值会自动进行 URL 编码，在取回时进行自动解码。
//为防止 URL 编码，请使用 setrawcookie() 取而代之。
//示例2
$expire=time()+60*60*24*30;
setcookie("user", "php", $expire);
//过期时间被设置为一个月（60 秒 * 60 分 * 24 小时 * 30 天）。
?>
<html>
.....How to retrieve the value of Cookie?
PHP’s $_COOKIE variable is used to retrieve the value of the cookie. The code is as follows:
<?php // 输出 cookie 值 echo $_COOKIE["user"]; // 查看所有 cookie print_r($_COOKIE); ?>
The running results are as follows:
Use the isset() function to confirm whether the cookie has been set:
Additional information about the usage of isset 0 function:
PHP’s isset() function - generally used to detect whether a variable is set
Format:
boolisset( mixed var [， mixed var[，...11 )
Function: Check whether the variable is set
Return value:
If the variable does not exist Then return FALSE
If the variable exists and its value is NULL, also return FALSE
- ##If the variable exists and its value If it is not NULL, TRUB will be returned. When multiple variables are checked at the same time, TRUB will be returned only when each single item meets the previous requirement. Otherwise, the result will be FALSE
The specific code is as follows:
<html> <head> <meta charset="utf-8"> <title>php中文网(php.cn)</title> </head> <body> <?php if (isset($_COOKIE["user"])) echo "欢迎来到 " . $_COOKIE["user"] . "!<br>"; else echo "普通访客!<br>"; ?> </body> </html>
The running results are as follows:
How to delete cookies?
When deleting a cookie, you should change the expiration date to a point in time in the past.
The code is as follows: <?php
// 设置 cookie 过期时间为过去 1 小时
setcookie("user", "", time()-3600);
?>
Recommended learning: "PHP Video Tutorial
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