What does var mean in php

The var variable in PHP contains script execution information and can be used to: obtain server environment information (such as server name, operating system) check request status (such as request method) access script information (such as script path) var is a Associative array, keys are strings and values ​​are scalars or arrays. Values ​​can be accessed via $var['key']. Note: "var" is deprecated in PHP 8.0 and higher, it is recommended to use $_SERVER, $_REQUEST, $_COOKIE and $_FILES instead.

The var variable in PHP

var is a built-in variable in PHP. It contains information about the current configuration and status of the executing script.

Purpose

• Get information about the server environment, such as server name, operating system, and PHP version.
• Check the status of the current request, such as request method and request headers.
• Access information about the script being executed, such as the script's path and the amount of memory used.

value

var A variable is an associative array whose keys are strings and whose values ​​are scalar values ​​or arrays. Here are some of the most commonly used keys in the var variable:

• SERVER: Contains information about the server environment.
• GET: Contains information about the current GET request.
• POST: Contains information about the current POST request.
• COOKIE: Contains information about the cookie in the current request.
• FILES: Contains information about the uploaded files in the current request.
• REQUEST: Contains information about the current request, including GET, POST, COOKIE, and FILES arrays.
• SCRIPT_NAME: The path of the current script.
• PHP_VERSION: PHP version.

Access

To access the value in a var variable, you can use the following syntax:

<code class="php">$value = $var['key'];</code>

Example

The following example demonstrates how to use the var variable to obtain information about the server environment:

<code class="php">echo "服务器名称： " . $var['SERVER']['SERVER_NAME'];
echo "操作系统： " . $var['SERVER']['OS'];
echo "PHP 版本： " . $var['PHP_VERSION'];</code>

Note

• var Variables are deprecated in PHP version 8.0 and later. The following alternative is recommended:

<code class="php">// 获取服务器环境信息
$server = $_SERVER;

// 获取请求信息
$request = $_REQUEST;

// 获取 cookie 信息
$cookies = $_COOKIE;

// 获取文件上传信息
$files = $_FILES;</code>

• var Variables can only be used during script execution and are lost when the script terminates.

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