Question

how can I prevent PHP from returning an Undefined variable error every time I try to check a variable if it has contents and that certain variable hasn’t been used yet? In my previous setup, I can check $_POST[’email’] even if I haven’t put anything into it yet. It simply returns a blank or empty result. That’s how I want my PHP setup to work but for the life of me, I can’t seem to find figure out how to configure it. 🙁

Example:

<?php
if ($_POST['info'] != '') {
  // do some stuff
}
?>
<form method="post">
<input type="text" name="info" />
<input type="submit" />
</form>

When you use the above script in a single PHP page and run it on my current setup, it returns an Undefined variable error. On my previous setup, that script worked like a charm. Can anyone share some light into this problem of mine. If you need further details, just say so and I will try to add more details to this post.

I know about the isset() checking but I don’t want to use it on all of my scripts. I want it to not be that restrictive about variables.

Answer 1

Most likely it’s not an error, but a Warning. You can set PHP not to display errors/warnings if you want. Just add this to the begining of your code:

ini_set('display_errors', 0);

Altough, I recommend you not to be lazy and have your code not display any errors, warnings, notices whatsoever, better safe than sorry.

And the preferred way to do what you want to do is

<?php
if (isset($_POST['info'])) {
  // do some stuff
}
?>
<form method="post">
<input type="text" name="info" />
<input type="submit" />
</form>