After the client sends a request message to the server, the server responds with a response message, which includes HTTP status codes.

Captured this request
Status Codes:
1XX–The received request is being processed (can be seen when the network is particularly slow).
2XX–The request has been successfully processed.
3XX–Redirection: 302
304: Already accessed and cached. The server returns a 304 status, indicating no processing was done. No changes, so no processing. Not Modified status.
4XX–Errors caused by issues on the client side. Incorrect URLs inputted by the client lead to a nonexistent page, returning 404.
5XX–Server-side issues. 503 (service is down or crashed)
: OK here is the explanation of the aforementioned status codes.
The most reliable explanations for HTTP status codes:
https://baike.baidu.com/item/HTTP%E7%8A%B6%E6%80%81%E7%A0%81/5053660?fr=aladdin

View the source code of the page, where the source code here and the page returned in the HTTP request are the same.
