$_SERVER is an Array that stores information about the server PHP is running on, such as headers, paths, and script locations. The entries in this array are created by the web server.
The $_SERVER Array is a 'superglobal' variable. This means that it is available in all scopes throughout a script, you can access it directly within functions or classes.
- To access an element of the superglobal $_SERVER array you can use the fallowing syntax:

$_SERVER['INDEX']
- 'INDEX' represents the name of the superglobal element to be accessed, it must be written in uppercase and within quotes.
  For example, to display the domain name where the script runs:
echo $_SERVER['SERVER_NAME'];
Here are some of the most used variables of the superglobal $_SERVER array:
- Let's see some examples with some of this $_SERVER variables.

1. Get the visitor's ip

<?php
$ip = $_SERVER['REMOTE_ADDR'];
echo $ip;
?>

2. Get directory name from the URL address of the php script

<?php
// for example, if the URL address of the php script is:  https://marplo.net/php-mysql/index.php?id=28
$adr = $_SERVER['PHP_SELF'];
$dir = dirname($adr);
echo $dir;                 // /php-mysql
?>

3. Get current page full URL in PHP

<?php
// check for https
$protocol = !empty($_SERVER['HTTPS']) ? 'https://' : 'http://';
// sets the full address
$url = $protocol. $_SERVER['HTTP_HOST']. $_SERVER['REQUEST_URI'];

echo $url;
?>

- A complete list with the superglobal $_SERVER Array you can find at the oficial page: Superglobal $_SERVER.

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Which HTML5 tag defines marked text? (can be used to highlight parts of text)
<mark> <embed> <span>
<p>Free corses: <mark>coursesweb.net</mark> for Web Development.</p>
Which CSS pseudo-class adds a style to an element when the mouse is over it?
:focus :hover :active
a:hover {
  font-weight: bold;
  color: #00da01;
}
Click on the function which returns a string value that represents the number rounded to the x digits after the decimal point.
toPrecision(x) toFixed(x) floor(x)
var num = 12.34567;
num = num.toFixed(2);
alert(num);       // 12.35
Indicate the PHP function which reads an entire file into an array.
[) file() readfile()
$arr = file("a_file.txt", FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
var_export($arr);
Superglobal $_SERVER Array

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