/devtools-network-reference/ -- Error from "Send form data" button

Please test /devtools-network-reference/ > Send form data button:

• When using github.io.
• When using localhost.
• Check errors in command prompt.
• Check errors in DevTools Console.
• Actual result: In Network tool > Requests table > form row > Payload tab: No Query String Parameters section; only a Form Data section. Compare:
  • Upstream png: https://developer.chrome.com/docs/devtools/network/reference/#payload
  • Live old png: https://learn.microsoft.com/en-us/microsoft-edge/devtools/network/reference#display-query-string-parameters

When using localhost, when click the Send form data button:

• Get errors in git bash:
  • "GET /.well-known/appspecific/com.chrome.devtools.json" Error (404): "Not found"
  • "POST /form-data-endpoint" Error (404): "Not found"
• In Console, error:
  • script.js:49 POST http://localhost:8080/form-data-endpoint net::ERR_ABORTED 405 (Method Not Allowed)
    (anonymous) @ script.js:49

~/GitHub/Demos/devtools-network-reference (main)
$ npx http-server
Starting up http-server, serving ./
http-server version: 14.1.1
[Thu Jul 17 2025 17:16:33 GMT-0700 (Pacific Daylight Time)]  "GET /" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36 Edg/138.0.0.0"
(node:33900) [DEP0066] DeprecationWarning: OutgoingMessage.prototype._headers is deprecated
(Use `node --trace-deprecation ...` to show where the warning was created)
[Thu Jul 17 2025 17:16:33 GMT-0700 (Pacific Daylight Time)]  "GET /.well-known/appspecific/com.chrome.devtools.json" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36 Edg/138.0.0.0"
[Thu Jul 17 2025 17:16:33 GMT-0700 (Pacific Daylight Time)]  "GET /.well-known/appspecific/com.chrome.devtools.json" Error (404): "Not found"
[Thu Jul 17 2025 17:16:36 GMT-0700 (Pacific Daylight Time)]  "POST /form-data-endpoint" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36 Edg/138.0.0.0"
[Thu Jul 17 2025 17:16:36 GMT-0700 (Pacific Daylight Time)]  "POST /form-data-endpoint" Error (404): "Not found"

Line 49:

Console tool after click Send form data button when not using localhost:

Start with the /devtools-network-reference/ demo and script.js around line 49, then run it with npx http-server and reproduce the Send form data request on localhost and github.io. Compare the Network Payload tab and Console output with the referenced screenshots; done means the request behaves as intended without the reported 404 or 405 errors.