Impossible to capture 503 even with AngularJS' http interceptor

问题

I'm wondering why I cannot capture the status 503 when I encounter the error. HTTP interceptor captures the error with a status of 0. Is it even possible? If so, can you provide a code please?

来源：https://stackoverflow.com/questions/28257824/impossible-to-capture-503-even-with-angularjs-http-interceptor