What does $_FILES means?
$_FILES is an associative array composed of items sent to the current script via the HTTP POST method.
$_FILES is an associative array composed of items sent to the current script via the HTTP POST method.
$_SERVER is an array including information created by the web server such as paths, headers, and script locations.
$GLOBALS is associative array including references to all variables which are currently defined in the global scope of the script.
The session_unregister() function unregister a global variable from the current session and the session_unset() function frees all session variables.
Sessions automatically end when the PHP script finishes executing but can be manually ended using the session_write_close().
A persistent cookie is permanently stored in a cookie file on the browser’s computer. By default, cookies are temporary and are erased if we close the browser.
You can propagate a session id via cookies or URL parameters.
The use of the function session_start() lets us activating a session.
A session is a logical object enabling us to preserve temporary data across multiple PHP pages.
1- Combining two variables as follows: $variable1 = 'Hello '; $variable2 = 'World'; $variable3 = $variable1.$variable2; Or 2- $variable3 = "$variable1$variable2"; $variable3 will contain “Hello World”. The first code is…