Protocol on handling empty checkbox values

Hi all. For a universal form script I'm writing I want to store a 'Y' in a table field if a checkbox is checked and an 'N' if it's not. The problem is that when the form is posted if the checkbox is not checked the checkbox variable is not passed. E.g. <form method=POST action=submit.php> <input type=checkbox name=my_checkbox_var value=Y> </form> If the checkbox is checked, I get $_POST['my_checkbox_var'] == 'Y', but if not $_POST['my_checkbox_var'] is not even set. So what I've been doing is putting the variable names of the checkbox fields into an array, serializing it, and then pass the string as a hidden input on the form. Then in the page that handles the POST I unserialize the array to determine if checkbox fields were passed and then handle accordingly. But I'm wondering is there a better way (or at least a standard way) of doing this? David