Do checkbox inputs only post data if they're checked?

Question

Is it standard behaviour for browsers to only send the checkbox input value data if it is checked upon form submission?

And if no value data is supplied, is the defa

Answer 1

Just like ASP.NET variant, except put the hidden input with the same name before the actual checkbox (of the same name). Only last values will be sent. This way if a box is checked then its name and value "on" is sent, whereas if it's unchecked then the name of the corresponding hidden input and whatever value you might like to give it will be sent. In the end you will get the $_POST array to read, with all checked and unchecked elements in it, "on" and "false" values, no duplicate keys. Easy to process in PHP.