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

input type="hidden" name="is_main" value="0"

input type="checkbox" name="is_main" value="1"

so you can control like this as I did in the application. if it checks then send value 1 otherwise 0