About ajax jqXHR.getResponseHeaders('Date') returns null solution

Reference article: https://blog.csdn.net/HansExploration/article/details/85060612

Reason: back-end reasons. Because of W3C regulations, the server and cors do various confirmations.

Solution: add header header Access-Control-Expose-Headers:* on the server side

Php writing method: header('Access-Control-Expose-Headers:*');
After adding it, you can use getResponseHeader to get the content of all headers.