javascript - When using vue-resource to call the interface, why can't the data returned by the interface be seen and the browser displays it as null?

Question

As mentioned, use vue-resource to call the backend api

The back-end returns the front-end data as shown in the figure

Front-end parameters:

Code

There is data returned by the backend, but it is displayed as null on the browser. I am curious why it is displayed like this. If the returned data can be changed to be invisible to the user, can the security of the data be improved?
ps:
1.You can see the returned data under chrome
2.My firefox version is 49

Answer 1

You can see if you can see the response body when you open other web pages in Firefox

Answer 2

Since the response in the browser is null, it means there is no data. Where did you come to the conclusion that the backend has data. It is recommended to use tools such as postman to test the interface