Question

I want to check/filter user input. If, for example, the user chosen value does not match what we have on the db, I want the script/query to stop–obviously for security reasons.

Which is correct?

if (!floatval($esc_size || $esc_sizeid) )
    {
    echo "Invalid Size </br>";

    $thread_id = mysqli_thread_id($con);

/* Kill connection */
mysqli_kill($link, $thread_id);
    mysqli_close($link);
    }

or just simply

exit;

or is there a better, more secure way?

Thanks,
Jen

Answer 1

exit() will stop the script completely. PHP runs server-side and you are in complete control of what code is executed. For that reason, security is not an issue here.

From a user interface perspective, it is much better to put any updates to the db etc. in an if statement that only runs if the user input was valid and if it was not, display a friendly message to the user about what he/she did wrong.