Purpose
This page is intentionally stored as Windows-31J (CP932) bytes and declares Shift_JIS. Open its URL through Caido and inspect the original HTTP response, the rendered body, and the behavior when the message is sent to Replay.
This is an actual non-UTF-8 HTML response only when the web server sends the matching HTTP charset header. See the server-header check below.
Test case 1 - Basic Japanese text
�����E�Ђ炪�ȁE�J�^�J�i�B�������������ɕ\������邱�ƁB
Test case 2 - Shift_JIS trail bytes containing 0x5C
These characters have multi-byte representations whose second byte is 0x5C in Shift_JIS / Windows-31J. This can expose software that incorrectly treats raw text bytes as UTF-8 or mishandles backslash bytes.
�\ 95 5C �\ 83 5C �\ 8F 5C �\ 90 5C �\ 94 5C
Test case 3 - Windows-31J extension characters
This line includes characters available in Windows-31J / CP932, including vendor extensions and compatibility characters. Some are not representable in strict Shift_JIS implementations, so differences between Shift_JIS and CP932 handling may be visible.
HTTP response diagnostics
Browser-detected document encoding: Checking...
HTTP Content-Type returned by the server: Checking...
Checking whether the response headers match this test case.
Expected response header: Content-Type: text/html; charset=Shift_JIS
Important: the HTTP Content-Type charset takes precedence over the HTML meta declaration in normal browser decoding. If the server sends charset=UTF-8, the page may be decoded incorrectly and the test will not be valid. Configure the server to send charset=Shift_JIS (or serve the body without a conflicting charset declaration).
Suggested verification steps
- Open this URL through Caido and confirm that the raw response body is preserved.
- Confirm that the Japanese text above is readable in the response viewer, not only in the browser-rendered page.
- Send the response or a request containing the same text to Replay and check for mojibake or byte changes.
- Pay particular attention to the
0x5Ctrail-byte examples and the CP932 extension characters.
Scope note: one static HTML file can exercise one HTTP response encoding at a time. Separate endpoints or server-generated responses are needed to test EUC-JP, ISO-2022-JP, and other encodings as actual HTTP response bodies.