[PHP] checkboxes, radio buttons and $_POST['']

[John-Erik Omland]

Hi

HELP!!!

I have read through the manual about using $_POST['<name>'] to retrieve data from forms, but what happens when a form element is not filled in or checked?

If I have a checkbox on a form called "chk1" I get an error from PHP when I try this:
$chk1 = $_POST['chk1']; // error if user did not chech the checkbox on the form!!!

How do ya usefully retrieve the fact that a form element has not been filled in/checked?

Be Well,

John-Erik Omland

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"Rhythm is the basis of life,
not steady forward progress.
The forces of creation, destruction, and preservation
have a whirling, dynamic interaction."
                                        - Kabbalah