Javascript-Cross-origin Data Retrieval

When reading data from your server, you cannot obtain the data from the following external sources, and add the header (& #039; content-type: application: json; charsetutf8 & #039;); header (& #039; access-Control-Allow-Origin: * & #039;); header (& #039; Access-Control-Allow-Methods: POST & #039 ;); header (...

When reading data from your own server

Data cannot be obtained externally.
Header ('content-type: application: json; charset = utf8 ');
Header ('access-Control-Allow-Origin :*');
Header ('access-Control-Allow-Methods: Post ');
Header ('access-Control-Allow-Headers: x-requested-with, content-type ');
After

Why are the following results in json format different from those received?

Reply content:

When reading data from your own server

Data cannot be obtained externally.
Header ('content-type: application: json; charset = utf8 ');
Header ('access-Control-Allow-Origin :*');
Header ('access-Control-Allow-Methods: Post ');
Header ('access-Control-Allow-Headers: x-requested-with, content-type ');
After

Why are the following results in json format different from those received?

Jsonp for cross-origin Data Retrieval

It is clearly written that an array containing two elements and the data passed throughJSON.strigify()AndJSON.parse()Can be converted to each other.

... Special interfaces are required for cross-origin, not any interface for returning data.
Jsonp, script, and other labels are required. The returned result is a function with parameters instead of simple data...
Between...

Of course, the json format can be an array, a string, or an object.

JSON.parse('true');JSON.parse('false');JSON.parse('1');JSON.parse('0');JSON.parse('"hello"');JSON.parse('""');JSON.parse('[]');JSON.parse('{}');

Theoretically, JSON objects can be correctly converted by json. parse. At the same time, we also need to distinguish what is a json string and what is a json object.

header('content-type:application:json;charset=utf8');
The browser directly parses the result as json.

One is a string and the other is json, so there is no difference... just convert it.