demo · v139
Content-Type Validator for Japanese Text
Chrome 139 removes the auto-detection heuristic that sniffed ISO-2022-JP encoding from HTML bytes. Pages that relied on implicit charset detection now need an explicit charset declaration. Paste Japanese text, see how each encoding behaves, and validate your Content-Type header and <meta> tag against the new rules.
Japanese text input
Encoding comparison
| Encoding | Byte length | Chrome 139 status | Rendered |
|---|
Validate Content-Type header
Paste a Content-Type header value your server sends (e.g. text/html or text/html; charset=utf-8)
Boundary case matrix
Choose a real deployment shape. The controls above are filled in, then the page compares the Chrome 138 sniffing branch with the Chrome 139 explicit-only branch.
Fix my page — meta charset checker
Enter the charset value from your <meta charset="…"> or <meta http-equiv="Content-Type" …>
UTF-8 byte inspector
Live hex dump of the input text encoded as UTF-8. Multi-byte sequences for Japanese characters are highlighted.
Explicit decoder probe
Chrome 139 removes HTML auto-detection, not the ability to explicitly decode supported labels. This live probe uses TextDecoder to show which labels this browser still accepts when code names the encoding directly.