“Notice: Undefined variable”, “Notice: Undefined index”, and “Notice: Undefined offset” using PHP

Question

I\'m running a PHP script and continue to receive errors like:

Notice: Undefined variable: my_variable_name in C:\\wamp\\www\\mypath\\index.php on line 10

Answer 1

I used to curse this error, but it can be helpful to remind you to escape user input.

For instance, if you thought this was clever, shorthand code:

// Echo whatever the hell this is

...Think again! A better solution is:

// If this is set, echo a filtered version

(I use a custom html() function to escape characters, your mileage may vary)