PHP provides a large number of predefined variables to any script which it runs. PHP
provides an additional set of predefined arrays containing variables from the web server
the environment, and user input. These new arrays are called superglobals:
Variable | Description |
$GLOBALS | Contains a reference to every variable which is currently available
within the global scope of the script. The keys of this array are the
names of the global variables. |
$_SERVER | This is an array containing information such as headers, paths, and
script locations. The entries in this array are created by the web
server. There is no guarantee that every web server will provide any
of these. See next section for a complete list of all the SERVER
variables. |
$_GET | An associative array of variables passed to the current script via the
HTTP GET method. |
$_POST | An associative array of variables passed to the current script via the
HTTP POST method. |
$_FILES | An associative array of items uploaded to the current script via the
HTTP POST method. |
$_REQUEST | An associative array consisting of the contents of $_GET, $_POST, and
$_COOKIE. |
$_COOKIE | An associative array of variables passed to the current script via HTTP
cookies. |
$_SESSION | An associative array containing session variables available to the
current script. |
$_PHP_SELF | A string containing PHP script file name in which it is called. |
$php_errormsg | $php_errormsg is a variable containing the text of the last error
message generated by PHP. |
$_SERVER is an array containing information such as headers, paths, and script locations.
The entries in this array are created by the web server. There is no guarantee that every
web server will provide any of these.
Variable | Description |
$_SERVER['PHP_SELF'] | The filename of the currently executing
script, relative to the document root |
$_SERVER['argv'] | Array of arguments passed to the script.
When the script is run on the command line,
this gives C-style access to the command line
parameters. When called via the GET method,
this will contain the query string. |
$_SERVER['argc'] | Contains the number of command line
parameters passed to the script if run on the
command line. |
$_SERVER['GATEWAY_INTERFACE'] | What revision of the CGI specification the
server is using; i.e. 'CGI/1.1'. |
$_SERVER['SERVER_ADDR'] | The IP address of the server under which the
current script is executing. |
$_SERVER['SERVER_NAME'] | The name of the server host under which the
current script is executing. If the script is
running on a virtual host, this will be the
value defined for that virtual host. |
$_SERVER['SERVER_SOFTWARE'] | Server identification string, given in the
headers when responding to requests. |
$_SERVER['SERVER_PROTOCOL'] | Name and revision of the information protocol
via which the page was requested; i.e.
'HTTP/1.0'; |
$_SERVER['REQUEST_METHOD'] | Which request method was used to access the
page; i.e. 'GET', 'HEAD', 'POST', 'PUT'. |
$_SERVER['REQUEST_TIME'] | The timestamp of the start of the request.
Available since PHP 5.1.0. |
$_SERVER['QUERY_STRING'] | The query string, if any, via which the page
was accessed. |
$_SERVER['DOCUMENT_ROOT'] | The document root directory under which the
current script is executing, as defined in the
server's configuration file. |
$_SERVER['HTTP_ACCEPT'] | Contents of the Accept: header from the
current request, if there is one. |
$_SERVER['HTTP_ACCEPT_CHARSET'] | Contents of the Accept-Charset: header from
the current request, if there is one. Example:
'iso-8859-1,*,utf-8'. |
$_SERVER['HTTP_ACCEPT_ENCODING'] | Contents of the Accept-Encoding: header
from the current request, if there is one.
Example: 'gzip'. |
$_SERVER['HTTP_ACCEPT_LANGUAGE'] | Contents of the Accept-Language: header
from the current request, if there is one.
Example: 'en'. |
$_SERVER['HTTP_CONNECTION'] | Contents of the Connection: header from the
current request, if there is one. Example:
'Keep-Alive'. |
$_SERVER['HTTP_HOST'] | Contents of the Host: header from the current
request, if there is one. |
$_SERVER['HTTP_REFERER'] | The address of the page (if any) which
referred the user agent to the current page. |
$_SERVER['HTTP_USER_AGENT'] | This is a string denoting the user agent being
which is accessing the page. A typical
example is: Mozilla/4.5 [en] (X11; U; Linux
2.2.9 i586). |
$_SERVER['HTTPS'] | Set to a non-empty value if the script was
queried through the HTTPS protocol. |
$_SERVER['REMOTE_ADDR'] | The IP address from which the user is viewing
the current page. |
$_SERVER['REMOTE_HOST'] | The Host name from which the user is viewing
the current page. The reverse dns lookup is
based off the REMOTE_ADDR of the user. |
$_SERVER['REMOTE_PORT'] | The port being used on the user's machine to
communicate with the web server. |
$_SERVER['SCRIPT_FILENAME'] | The absolute pathname of the currently
executing script. |
$_SERVER['SERVER_ADMIN'] | The value given to the SERVER_ADMIN (for
Apache) directive in the web server
configuration file. |
$_SERVER['SERVER_PORT'] | The port on the server machine being used by
the web server for communication. For
default setups, this will be '80'. |
$_SERVER['SERVER_SIGNATURE'] | String containing the server version and
virtual host name which are added to servergenerated
pages, if enabled. |
$_SERVER['PATH_TRANSLATED'] | Filesystem based path to the current script. |
$_SERVER['SCRIPT_NAME'] | Contains the current script's path. This is
useful for pages which need to point to
themselves. |
$_SERVER['REQUEST_URI'] | The URI which was given in order to access
this page; for instance, '/index.html'. |
$_SERVER['PHP_AUTH_DIGEST'] | When running under Apache as module doing
Digest HTTP authentication this variable is set
to the 'Authorization' header sent by the
client. |
$_SERVER['PHP_AUTH_USER'] | When running under Apache or IIS (ISAPI on
PHP 5) as module doing HTTP authentication
this variable is set to the username provided
by the user. |
$_SERVER['PHP_AUTH_PW'] | When running under Apache or IIS (ISAPI on
PHP 5) as module doing HTTP authentication
this variable is set to the password provided
by the user. |
$_SERVER['AUTH_TYPE'] | When running under Apache as module doing
HTTP authenticated this variable is set to the
authentication type. |