How to operate Session and Cookie in PHP_php tips

Session
PHP's $_SESSION can store the current user data information. When a user visits a WEB website, PHP will create a session ID for each visiting user. This ID is a unique ID and is saved on the client, while the user's session data is saved to On the server side, PHP can store each different user information. When the session expires, the user session information will also become invalid.
When using Session, when using PHP session, be sure to add session_start() to the header of the page to tell the server to start using the session, and there should be no output before it, otherwise an error will be reported.

<&#63;php 
session_start(); 
 
//PHP 代码... 
&#63;> 

PHP setting and obtaining Session
We can use PHP’s $_SESSION to set and get Session data, such as:

<&#63;php 
session_start();  
 
//设置一个session值 
$_SESSION["name"] = "Hello"; 
 
//将session以数组形式保存 
$_SESSION["arr"] = array('name' => 'Hello', 'url' => 'http://www.helloweba.com', 'type'=> 'website'); 
&#63;> 

Once the Session data is stored, we can use the Session on the website. For example, we can obtain the Session data on another page:

<&#63;php 
session_start();  
 
//获取保存的Session name 
echo $_SESSION["name"]; 
 
//打印数组session 
print_r($_SESSION["arr"]); 
&#63;> 

PHP Delete Session
When the Session is no longer used, we can use PHP to delete and clear the session data. The method is as follows:

<&#63;php 
unset($_SESSION["name"]); 
&#63;> 

If you want to clear all session information of the current user, you can use the following code:

<&#63;php 
session_destroy(); 
&#63;> 

Cookie
Cookie is a temporary file created on the current client computer by the website server visited by the user. It is used to save user information so that the website server can identify the user information when the user continues to visit the website next time. Common cookies are used to Save user interface, user ID and other data.
PHP Set Cookie
We can use PHP's setcookie() to create cookies on the client. This function provides three main parameters, cookie name, value and validity period.

<&#63;php 
$cookie_val = 'Chrome'; 
setcookie("browser", $cookie_val, time()+3600); 
&#63;> 

Running the above code will create a cookie named Chrome and save it on the client for 1 hour. The cookie information will expire after 1 hour.
PHP receives Cookie
After the cookie is created, we can easily get the cookie value by using PHP's $_COOKIE. The usage is as follows:

<&#63;php 
if(isset($_COOKIE['browser'])) { 
  echo '您的浏览器是：' . $_COOKIE['browser']; 
} 
&#63;> 

PHP Delete Cookie
If you want to completely delete the saved cookie information on your machine, you can use the following code:

<&#63;php 
setcookie("browser", "", time()-3600); 
&#63;> 

The above code clears the cookie named browser and sets the validity period to 1 hour ago, completely clearing the cookie information.
This article considers from the perspective of beginners and explains the entry-level knowledge of PHP: the application of Session and Cookie. We do not need to delve into the principles, as long as we can use it.