I have a problem. I created a simple model and tried to save new value by using it through ajax request. But parameters which must be empty sends default value. You can see it by link under. The code does not specifically set the correct way bacause of what the console(f12) can be seen fallen challenge. In it I pass a value through a query-string, as well as through the payload-request (not yet invented how to get rid of it, as I understand it-payload is used by default). In general, instead of an empty carId call transfers Car-1.
https://fiddle.sencha.com/#fiddle/dsj
How do I fix this behavior and do that if we do not share any meaning, it passed empty?