predefined variables in PHP called "super global", which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special.
Below are Super global,
1) $GLOBALS
2) $_SERVER
3) $_REQUEST
4) $_POST
5) $_GET
6) $_FILES
7) $_ENV
8) $_COOKIE
9) $_SESSION
1) $GLOBALS - means accessible variables outside of function , for example - $GLOBALS['z'] this variable also accessible outside function 'addition'
<?php
$x = 75;
$y = 25;
function addition() {
$GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y'];
}
addition();
echo $z;
?>
2) $_SERVER -
$_SERVER['PHP_SELF'] - current PHP file name
$_SERVER['GATEWAY_INTERFACE'] - version of the Common Gateway Interface (CGI) currently using
$_SERVER['SERVER_ADDR'] - Host server IP address
$_SERVER['SERVER_NAME'] - name of the host server (such as infyleaf.tech)
$_SERVER['REQUEST_METHOD'] request method used to access the page (such as POST)
$_SERVER['QUERY_STRING'] query string if the page is accessed via a query string
$_SERVER['HTTP_ACCEPT'] Accept header from the current request
$_SERVER['HTTP_ACCEPT_CHARSET'] Accept Charset header from the current request
$_SERVER['HTTP_HOST'] Host header from the current request
$_SERVER['HTTP_REFERER'] complete URL of the current page (not reliable because not all user-agents support it)
$_SERVER['HTTPS'] Is the script queried through a secure HTTP protocol
$_SERVER['REMOTE_ADDR'] IP address from where the user is viewing the current page
$_SERVER['REMOTE_HOST'] Host name from where the user is viewing the current page
$_SERVER['REMOTE_PORT'] port being used on the user's machine to communicate with the web server
$_SERVER['SCRIPT_FILENAME'] absolute pathname of the currently executing script
$_SERVER['PATH_TRANSLATED'] file system based path to the current script
$_SERVER['SCRIPT_NAME'] path of the current script
$_SERVER['SCRIPT_URI'] URI of the current page
3) $_REQUEST - get requested name $name = $_REQUEST['fname']; when form is post
4) $_POST - when post form get value of input for eg -
$_POST['firstname'], $_POST['mobile']
<form action="" method="post">
<input type="text" name="mobile"/>
<input type="submit" value="save"/>
</form>
5) $_GET - get value from url , but should remember not pass secure value like password to this variable.
6)$_FILES - to get value from files when post input type file
basename($_FILES["fileToUpload"]["name"]);
for example
if ($_FILES["fileToUpload"]["size"] > 2000000) {
echo "Sorry, your file is too large.";
$uploadOk = 0;
}
7)$_ENV - get environment variables
<?php
$arr=getenv();
foreach ($arr as $key=>$val)
echo "$key=>$val
";
?>
8) $_COOKIE - get cookie value
in below example checking if cookie name set or not
<?php
$cookie_name = "user";
$cookie_value = "Mayur";
setcookie($cookie_name, $cookie_value, time() + (86400 * 30), "/"); // 86400 = 1 day
?>
<html>
<body>
<?php
if(!isset($_COOKIE[$cookie_name])) {
echo "Cookie named '" . $cookie_name . "' is not set!";
} else {
echo "Cookie '" . $cookie_name . "' is set!<br>";
echo "Value is: " . $_COOKIE[$cookie_name];
}
?>
9) $_SESSION - store value in session , temporary storage over multiple page.
first line should be session_start();
$_SESSION["favcolor"] = "green";
in case any query please comment
