Character encoding auto-detection in JavaScript (port of python's chardet)
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aadsm Version 1.6.0
- Improve CharSet prober by filtering english characters (@tarnelope)
Latest commit 28152dd Oct 27, 2017



Port of python's chardet (



How To Use It


npm install jschardet
var jschardet = require("jschardet")

// "àíàçã" in UTF-8
// { encoding: "UTF-8", confidence: 0.9690625 }

// "次常用國字標準字體表" in Big5
// { encoding: "Big5", confidence: 0.99 }


Copy and include jschardet.min.js in your web page.

This library is also available in cdnjs at


// See all information related to the confidence levels of each encoding.
// This is useful to see why you're not getting the expected encoding.
jschardet.Constants._debug = true;

// Default minimum accepted confidence level is 0.20 but sometimes this is not
// enough, specially when dealing with files mostly with numbers.
// To change this to 0 to always get something or any other value that can
// work for you.
jschardet.Constants.MINIMUM_THRESHOLD = 0;

Supported Charsets

  • Big5, GB2312/GB18030, EUC-TW, HZ-GB-2312, and ISO-2022-CN (Traditional and Simplified Chinese)
  • EUC-JP, SHIFT_JIS, and ISO-2022-JP (Japanese)
  • EUC-KR and ISO-2022-KR (Korean)
  • KOI8-R, MacCyrillic, IBM855, IBM866, ISO-8859-5, and windows-1251 (Russian)
  • ISO-8859-2 and windows-1250 (Hungarian)
  • ISO-8859-5 and windows-1251 (Bulgarian)
  • windows-1252
  • ISO-8859-7 and windows-1253 (Greek)
  • ISO-8859-8 and windows-1255 (Visual and Logical Hebrew)
  • TIS-620 (Thai)
  • UTF-32 BE, LE, 3412-ordered, or 2143-ordered (with a BOM)
  • UTF-16 BE or LE (with a BOM)
  • UTF-8 (with or without a BOM)

Technical Information

I haven't been able to create tests to correctly detect:

  • ISO-2022-CN
  • windows-1250 in Hungarian
  • windows-1251 in Bulgarian
  • windows-1253 in Greek
  • EUC-CN


Use npm run dist to update the distribution files. They're available at


Ported from python to JavaScript by António Afonso (

Transformed into an npm package by Markus Ast (