Predefined or Superglobals variables are used to provide information from and about the web server, the web browser, and the user.
There are several types of Super Global Variables:-
$_GET – Is used to pass data through URL. Example: http://websjyoti.com?id=2
$_POST – Is used to pass data to server by hiding from URL.
$_REQUEST – Is the combination of $_GET, $_POST, and $_COOKIE.
$_SESSION – is used to maintain session and data from Local machine to Server.
$_COOKIE – Is used to save/get user data on same machine in browser cookies.
$_SERVER – Is an associative array which is used to know server information i.e. IP address, Host name, query string, file name etc.
$_FILES – Is used to handle uploaded files operations in PHP. i.e. file size, type, name etc.
Example – $_SERVER Superglobals
echo “Current IP Address is : “.$_SERVER[‘REMOTE_ADDR’];
echo “You are Page at : ” . $_SERVER[‘PHP_SELF’];
Functions in PHP behave similarly to functions in C. When we define the functions, we must specify what values the function can expect to receive.
So let’s create a function. We need to give the function a name and tell it what variables to expect. We also need to define the function before we call it.
function sum($f1, $f2)
$f3 = $f1 + $s2;
So First, we created our function. Notice how we defined two new variables, called $f1 and $f2. When we call the function, each variable is assigned a value based on the order in which it appears. Then we simply added the two numbers together and returned the result. “Return” here simply means to send the result back.