How to transfer and maintain values between pages in PHP

This article mainly introduces the method of transferring and maintaining values between PHP pages. The transferred values are mainly submitted through get and post, and the data is maintained through session and cookie. This article introduces it in very detail and has reference value. Friends in need You can refer to the following

1. Directory structure

##2. Transferring values between two pages

# To transfer a small amount of data between two pages, you can use get to submit or post. Submit, the difference between the two will not be elaborated.

　1. Get submission

Use get submission to transfer data, and modify the URL sent to the server in the link address as shown below http: //www.cnblogs.com/MarkRao/p/php01.html?gName=mark&gAge=26, of course, you can also set method="get" in the form, and receive the data value submitted by get in php, using the predefined $_GET Variable

Information sent from a form with the GET method is visible to anyone (will be displayed in the browser's address bar), and there is a limit on the amount of information sent.

    
  
 名字:  年龄:   
  

The "getPage.php" file can now collect form data via the $_GET variable (note that the name of the form field will automatically become $_GET key in the array):

1 欢迎 !
 2 你的年龄是  岁。

##　2. Post submission

Use post submission to transfer data, set method="post" in the form, receive the data value submitted by post in php, use the predefined $_POST variable

Information sent from the form with the POST method , is invisible to anyone (will not show up in the browser's address bar), and there is no limit on the amount of information sent.

Note: However, by default, the maximum amount of information sent by the POST method is 8 MB (can be changed by setting post_max_size in the php.ini file).

    
  
 名字:  年龄:   
  

The "postPage.php" file can now collect form data through the $_POST variable (note that the name of the form field will automatically become Key in the $_POST array):

欢迎 !
 你的年龄是  岁。

3. Maintain values between multiple pagesTo maintain data between multiple pages, you can use session to save it, or you can use cookie to save it. The difference between the two will not be described in detail.

1. Session save data

The PHP session variable is used to store information about the user session (session), or to change the user session (session) )setting. Session variables store information for a single user and are available to all pages in the application. The working mechanism of Session is to create a unique ID (UID) for each visitor and store variables based on this UID. The UID is stored in a cookie or passed through the URL.

Before you can store user information in a PHP session, you must first start the session.

Note: The session_start() function must be located before the 100db36a723c770d327fc0aef2ce13b1 tag:

The correct way to store and retrieve session variables is to use PHP’s $_SESSION variable:

2. Cookies save data

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, you can create and retrieve cookie values.

The setcookie() function is used to set cookies.

Note: The setcookie() function must be located before the 100db36a723c770d327fc0aef2ce13b1 tag.

The syntax is as follows

//name存储的键名 //value存储的键值 //expire存储的超时时间 //path存储的位置 //domain存储区别的域名 setcookie(name, value, expire, path, domain);

The $_COOKIE variable is used to retrieve the value of the cookie.

When deleting a cookie, you should change the expiration date to a point in time in the past:

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's study.

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