php-Pre-Def variable

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General

A superglobal is a predef var, that is alwaysa ccessible, regardless of scope.

Yu can access the PHP superglobalsthrough function, class or file.

Superglobal variables

$_SERVER

$GLOBALS

$REQUEST

$_POST

$_GET

$_FILES

$_ENV

$_COOKIE

$_SESSION

$SERVER

it returns the path of the current script. Includes: headers, paths, K script location.

<?php

echo $_SERVER[`SCRIPT_NAME`];

?> //   /Playground/file().php

elements for $_SERVER

Some of the most important elements going inside $Server

$_SERVER[`SERVER_NAME`]

$_SERVER[`REQUEST_METHOD`]

$_SERVER[`QUERY_STRING`]

$_SERVER[`HTTP_HOST`]

$_SERVER[`REMOTE_ADDR`]

$_SERVER[`REMOTE_HOST`]

$_SERVER[`SERVER_PORT`]

$_SERVER[`SCRIPT_NAME`]

$_SERVER[`SCRIPT_URI`]

$_SERVER variable: Host name

$_SERVER[`HTTP_HOST`]

Returns the host header from the current request

 <?php

echo $_SERVER[`HTTP_HOST']; // output "localhost"

?>

Exemple:

To transfer website to another host, instead of changing the path for each image, create a config.php file that holds the path for your images:

<?php

$host=$_SERVER['HTTP_HOST'];

$image_path=$host.'/images/';

?>

use config.php file in your scripts

<?php

require 'config.php';

echo'<img src='.$image_path.'header.png' />';

?>

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