Weak typing in PHP: why use isset at all?

Question

It seems like my code works to check for null if I do

if ($tx) 

or

if (isset($tx))

why would I do the se

Answer 1

The first one only works depending on how your server is configured. On many production servers, it will break.

Use isset() and be merry.

Or, try your code with the following at the top of the PHP source and watch it break:

ini_set('display_errors', 1);
error_reporting(E_ALL);