$_REQUEST

$_REQUEST is a PHP superglobal variable that contains the contents of both $_GET, $_POST, and $_COOKIE. It is used to collect data sent via both the GET and POST methods, as well as cookies. $_REQUEST is useful if you do not care about the method used to send data, but its usage is generally discouraged as it could lead to security vulnerabilities. Here's a simple example:

$name = $_REQUEST['name'];

This statement will store the value of the 'name' field sent through either a GET or POST method. Always remember to sanitize user input to avoid security problems.