Get URL query string parameters

For example, if  this our URL is:
 http://www.example.com/page.php?x=100&y=200
 the code is here :
<?php 

$arr= array();
parse_str($_SERVER['QUERY_STRING'], $arr);
will store 'x' = 100 and 'y' = 200 in $queries

echo $arr['x'];
echo $arr['y'];

output: 100,200

?>
Notes:The function parse_str() automatically reads all query parameters into an array.

Here is another super global in php.

$_SERVER['PHP_SELF']  : Returns the filename of the currently executing script
$_SERVER['GATEWAY_INTERFACE'] : Returns the version of the Common Gateway Interface (CGI) the server is using
$_SERVER['SERVER_ADDR'] :  Returns the IP address of the host server
$_SERVER['SERVER_NAME'] :  Returns the name of the host server (such as https://wptutorialpoints.blogspot.com)
$_SERVER['SERVER_SOFTWARE']:  Returns the server identification string (such as Apache/2.2.24)
$_SERVER['SERVER_PROTOCOL']  :  Returns the name and revision of the information protocol (such as HTTP/1.1)
$_SERVER['REQUEST_METHOD']  :  Returns the request method used to access the page (such as POST)
$_SERVER['REQUEST_TIME'] : Returns the timestamp of the start of the request (such as 1377687496)
$_SERVER['QUERY_STRING']  : Returns the query string if the page is accessed via a query string
$_SERVER['HTTP_ACCEPT'] : Returns the Accept header from the current request
$_SERVER['HTTP_ACCEPT_CHARSET'] : Returns the Accept_Charset header from the current request (such as utf-8,ISO-8859-1)
$_SERVER['HTTP_HOST'] : Returns the Host header from the current request
$_SERVER['HTTP_REFERER']  : Returns the complete URL of the page from which the current page was called
$_SERVER['HTTPS'] : Is the script queried through a secure HTTP protocol
$_SERVER['REMOTE_ADDR']  : Returns the IP address from where the user is viewing the current page
$_SERVER['REMOTE_HOST'] :  Returns the Host name from where the user is viewing the current page
$_SERVER['REMOTE_PORT']  : Returns the port being used on the user's machine to communicate with the web server
$_SERVER['SCRIPT_FILENAME'] : Returns the absolute pathname of the currently executing script
$_SERVER['SERVER_ADMIN']  : Returns the value given to the SERVER_ADMIN directive in the web server configuration file (if your script runs on a virtual host, it will be the value defined for that virtual host) (such as someone@w3schools.com)
$_SERVER['SERVER_PORT']  :  Returns the port on the server machine being used by the web server for communication (such as 80)
$_SERVER['SERVER_SIGNATURE']  : Returns the server version and virtual host name which are added to server-generated pages
$_SERVER['PATH_TRANSLATED']   : Returns the file system based path to the current script
$_SERVER['SCRIPT_NAME']   : Returns the path of the current script
$_SERVER['SCRIPT_URI']  : Returns the URI of the current page