I had never noticed before that submitting a form with unchecked checkboxes in it results in those checkboxes not being sent to the server at all. I had always assumed that a zero ( 0 ) would be sent for unchecked since a one ( 1 ) is sent when checked. Rather than add code to specifically handle these individual checkboxes, you can just add hidden inputs above the checkboxes in the HTML with a value of zero like this:

<input type="hidden" name="box1" value="0" /> <input type="checkbox" name="box1" value="1" />

This is a much simpler solution that doesn’t require writing any additional code or sending an array of checkboxes. I chose this method since I was using an automated Settings saver in PHP so it would be a pain to modify it and it could make the code more dirty.

Thanks to iamcam for writing about this.