About the Magic constants of PHP

$_server stores current server information, with several values such as $_server["Query_string"],$_server["Request_uri"],$_server["Script_name" and $_server[" Php_self "] often easy to confuse, the following through the example of the $_server function in the query_string,request_uri,script_name and php_self variable differences, master the relationship between the four, It is convenient to obtain the required value correctly in practical application for reference.
1,$_server["Query_string"]
Description: A string that queries (query)
2,$_server["Request_uri"]
Description: The URI required to access this page
3,$_server["Script_name"]
Description: Contains the path of the current script
4,$_server["Php_self"]
Description: The file name of the currently executing script
Instance:
1,http://www.biuuu.com/(open homepage directly)
Results:
$_server["query_string"] = ""
$_server["Request_uri"] = "/"
$_server["script_name"] = "/index.php"
$_server["php_self"] = "/index.php"
2,http://www.biuuu.com/?p=222 (with inquiry)
Results:
$_server["query_string"] = "p=222"
$_server["Request_uri"] = "/?p=222"
$_server["script_name"] = "/index.php"
$_server["php_self"] = "/index.php"
3,http://www.biuuu.com/index.php?p=222&q=biuuu
Results:
$_server["query_string"] = "p=222&q=biuuu"
$_server["Request_uri"] = "/index.php?p=222&q=biuuu"
$_server["script_name"] = "/index.php"
$_server["php_self"] = "/index.php"
$_server["Query_string"] gets the query statement, in the instance, gets the following value
$_server["Request_uri"] gets the value after http://www.biuuu.com, including/
$_server["Script_name"] gets the path to the current script, such as: index.php
$_server["Php_self"] The file name of the script that is currently executing
To summarize, for Query_string,request_uri,script_name and php_self, deep understanding will help us to correctly invoke these four values in the $_server function. The differences between the four variables are mastered by Query_string,request_uri,script_name and php_self in the $_server function by example.

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