How to fix ‘Notice: Undefined index:’ in PHP form action
Assuming you only copy/pasted the relevant code and your form includes <form method=”POST”> If _POST is not set the filename variable won’t be either in the above example. An alternative way: In this example filename is set regardless of the situation with _POST. This should demonstrate the use of isset nicely. More information here: http://php.net/manual/en/function.isset.php