Question

I’d like to separate two things.

If a $_POST["something"] was sent, BUT empty.

OR

If a $_POST["something"] was not sent.

Is there a way?

Answer 1

You might be tempted to use empty(), but it blows up in your face if your possible values include a 0. Best to use something like:

if (isset($_POST['something'])) {
   // the form field was sent ...
   if ($_POST['something'] === '') {
      // the form field was sent, but is empty
   }
}

This works, as ALL data coming out of the _GET/_POST/_REQUEST superglobals is a string, regardless of whether it’s a number or not.