diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index af30d1c..0505a15 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -55,6 +55,7 @@ set(
 	nsSJISProber.cpp
 	nsUTF8Prober.cpp
 	nsLanguageDetector.cpp
+	nsCJKDetector.cpp
 	nsLatin1Prober.cpp
 	nsUniversalDetector.cpp
 	uchardet.cpp
diff --git a/src/nsCJKDetector.cpp b/src/nsCJKDetector.cpp
new file mode 100644
index 0000000..7ee7f31
--- /dev/null
+++ b/src/nsCJKDetector.cpp
@@ -0,0 +1,239 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla Universal charset detector code. This
+ * file was later added by Jehan in 2021 to add language detection.
+ *
+ * The Initial Developer of the Original Code is Netscape Communications
+ * Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 2001 the
+ * Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *          Jehan <zemarmot.net> (2021)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#define CJK_ENOUGH_CHAR_THRESHOLD     4096
+#define CJK_POSITIVE_SHORTCUT_THRESHOLD  (float)0.95
+#define CJK_NEGATIVE_SHORTCUT_THRESHOLD  (float)0.05
+
+#include "nsCJKDetector.h"
+
+void nsCJKDetector::Reset(void)
+{
+  nsLanguageDetector::Reset();
+
+  mHangulChar = 0;
+  mKanaChar   = 0;
+  mHanziChar  = 0;
+}
+
+nsDetectState nsCJKDetector::HandleData(const int* codePoints, PRUint32 cpLen)
+{
+  for (PRUint32 i = 0; i < cpLen; i++)
+  {
+    mTotalChar++;
+
+    if ((codePoints[i] >= 0xAC00 && codePoints[i] <= 0xD7A3) ||
+        (codePoints[i] >= 0x1100 && codePoints[i] <= 0x11FF) ||
+        (codePoints[i] >= 0x3130 && codePoints[i] <= 0x318F) ||
+        (codePoints[i] >= 0xA960 && codePoints[i] <= 0xA97F) ||
+        (codePoints[i] >= 0xD7B0 && codePoints[i] <= 0xD7FF))
+    {
+      mHangulChar++;
+    }
+    else if ((codePoints[i] >= 0x3041 && codePoints[i] <= 0x309F) ||
+             (codePoints[i] >= 0x30A0 && codePoints[i] <= 0x30FF))
+    {
+      mKanaChar++;
+    }
+    else if (codePoints[i] >= 0x4E00 && codePoints[i] <= 0x9FBF)
+    {
+      mHanziChar++;
+    }
+    else if (codePoints[i] <= 0x1F || codePoints[i] == 0x7F   || /* C0 */
+             (codePoints[i] <= 0x9F && codePoints[i] >= 0x80) || /* C1 */
+             /* Separators: not strictly control characters for the Unicode
+              * standard, but we'll consider as such in our purpose.
+              */
+             codePoints[i] == 0x2028 || codePoints[i] == 0x2029 ||
+             /* Tags: U+E0001 is deprecated but other are still usable as
+              * emoji identifiers. Not sure how to use them.
+              */
+             codePoints[i] == 0xE0001                           ||
+             /* Interlinear annotations. */
+             codePoints[i] == 0xFFF9 || codePoints[i] == 0xFFFA ||
+             codePoints[i] == 0xFFFB                            ||
+             /* Bidirectional text control. */
+             codePoints[i] == 0x061C || codePoints[i] == 0x200E ||
+             codePoints[i] == 0x200F ||
+             (codePoints[i] >= 0x202A && codePoints[i] <= 0x202E) ||
+             (codePoints[i] >= 0x2066 && codePoints[i] <= 0x2069) ||
+             /* Control pictures. */
+             (codePoints[i] >= 0x2400 && codePoints[i] <= 0x2426))
+      {
+        /* XXX: some control characters such as variation selectors may
+         * need to be considered separately (basically just as if they
+         * were not here and simply skipped?). */
+        //mCtrlChar++;
+      }
+      /* When encountering an illegal codepoint, no need
+       * to continue analyzing data. It means this is not right, hence
+       * that the encoding we deducted this codepoint from is wrong.
+       * Unfortunately listing all illegal codePoints in Unicode might be
+       * a daunting task and comparing each characters to all these
+       * illegal codePoints would be a lot of additional work. Is it
+       * really necessary? XXX
+       */
+      else if (/* Tab, line feed and carriage returns are common enough
+                * that they should be considered as commonly used characters.
+                */
+               codePoints[i] == 0x9 || codePoints[i] == 0xA || codePoints[i] == 0xd ||
+               (codePoints[i] >= 0x20 && codePoints[i] <= 0x40) ||
+               (codePoints[i] >= 0x5B && codePoints[i] <= 0x5F) ||
+               (codePoints[i] >= 0x7B && codePoints[i] <= 0x7E) ||
+               (codePoints[i] >= 0xA0 && codePoints[i] <= 0xA5) ||
+               (codePoints[i] >= 0xA0 && codePoints[i] <= 0xB4) ||
+               (codePoints[i] >= 0xB6 && codePoints[i] <= 0xBF) ||
+               codePoints[i] == 0xD7                            ||
+               codePoints[i] == 0xF7                            ||
+               /* General Punctuation */
+               (codePoints[i] >= 0x2000 && codePoints[i] <= 0x206F) ||
+               /* Vertical Forms */
+               (codePoints[i] >= 0xFE10 && codePoints[i] <= 0xFE1F) ||
+               /* CJK Symbols and Punctuation */
+               (codePoints[i] >= 0x3000 && codePoints[i] <= 0x303F) ||
+               /* Halfwidth and Fullwidth Forms */
+               (codePoints[i] >= 0xFF00 && codePoints[i] <= 0xFFEF))
+       {
+         /* Punctuations, various symbols, even numbers are simply
+          * ignored.
+          * As for halfwidth and fullwidth characters, I'm not sure what
+          * to do with them, but let's go with the same logics of
+          * skipping them, at least for now..
+          */
+         //mVariousBetween++;
+       }
+      else if (/* Common Ctrl except the ones considered as common chars. */
+               (codePoints[i] >= 0x1F600 && codePoints[i] <= 0x1F64F) ||
+               codePoints[i] == 0xFE0E || codePoints[i] == 0xFE0F     ||
+               (codePoints[i] >= 0x1F3FB && codePoints[i] <= 0x1F3FF) ||
+               /* Miscellaneous Symbols */
+               (codePoints[i] >= 0x2600 && codePoints[i] <= 0x26FF) ||
+               /* Supplemental Symbols and Pictographs */
+               (codePoints[i] >= 0x1F90C && codePoints[i] <= 0x1F93A) ||
+               (codePoints[i] >= 0x1F93C && codePoints[i] <= 0x1F945) ||
+               (codePoints[i] >= 0x1F947 && codePoints[i] <= 0x1F978) ||
+               (codePoints[i] >= 0x1F97A && codePoints[i] <= 0x1F9CB) ||
+               (codePoints[i] >= 0x1F9CD && codePoints[i] <= 0x1F9FF) ||
+               /* Miscellaneous Symbols and Pictographs */
+               (codePoints[i] >= 0x1F300 && codePoints[i] <= 0x1F5FF) ||
+               /* Transport and Map Symbols */
+               (codePoints[i] >= 0x1F680 && codePoints[i] <= 0x1F6FF) ||
+               /* Dingbat */
+               (codePoints[i] >= 0x2700 && codePoints[i] <= 0x27BF))
+      {
+        //mEmoticons++;
+      }
+      else
+      {
+        /* All the rest is to be considered as non-frequent characters.
+         * These are not disqualifying (we may also have a text with a bit
+         * of foreign quotes in it or very unusual characters sometimes)
+         * but they will drop a bit the confidence.
+         */
+        mOutChar++;
+      }
+    }
+
+  if (mState == STATE_DETECTING)
+    if (mTotalChar > CJK_ENOUGH_CHAR_THRESHOLD)
+    {
+      ComputeConfidence();
+      if (confidence > CJK_POSITIVE_SHORTCUT_THRESHOLD)
+        mState = STATE_FOUND;
+      else if (confidence < CJK_NEGATIVE_SHORTCUT_THRESHOLD)
+        mState = STATE_UNLIKELY;
+    }
+
+  return mState;
+}
+
+#include <cstdio>
+float nsCJKDetector::GetConfidence(void)
+{
+  ComputeConfidence();
+
+  return confidence;
+}
+
+const char* nsCJKDetector::GetLanguage()
+{
+  ComputeConfidence();
+
+  return language;
+}
+
+void nsCJKDetector::ComputeConfidence(void)
+{
+  float confKo = 0.01f;;
+  float confJa = 0.01f;;
+  float confZh = 0.01f;;
+  float all_chars    = (float) (mOutChar + mHanziChar + mHangulChar + mKanaChar);
+  float hangul_chars = (float) mHangulChar;
+  float hanzi_chars  = (float) mHanziChar;
+  float kana_chars   = (float) mKanaChar;
+
+  language   = NULL;
+  confidence = 0.01f;
+
+  if (mTotalChar > 0)
+  {
+    confKo = hangul_chars / all_chars;
+    language = "ko";
+    confidence = confKo;
+
+    confZh = hanzi_chars / all_chars;
+    if (confZh > confKo)
+    {
+      language = "zh";
+      confidence = confZh;
+    }
+
+    /* Japanese still uses a lot of Chinese characters, so I think this
+     * very naive confidence computation will need to be revised soon.
+     * We should probably compute statistics of hanzi / (hanzi + kana)
+     * characters and use this as a weight modifier.
+     */
+    confJa = (kana_chars + hanzi_chars / 2.0) / all_chars;
+    if (confJa > confidence)
+    {
+      language = "ja";
+      confidence = confJa;
+    }
+  }
+}
diff --git a/src/nsCJKDetector.h b/src/nsCJKDetector.h
new file mode 100644
index 0000000..6490aea
--- /dev/null
+++ b/src/nsCJKDetector.h
@@ -0,0 +1,70 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla Universal charset detector code. This
+ * file was later added by Jehan in 2021 to add language detection.
+ *
+ * The Initial Developer of the Original Code is Netscape Communications
+ * Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 2001 the
+ * Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *          Jehan <zemarmot.net> (2021)
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+#ifndef nsCJKDetector_h__
+#define nsCJKDetector_h__
+
+#include "nsLanguageDetector.h"
+
+class nsCJKDetector: public nsLanguageDetector {
+public:
+  nsCJKDetector(): nsLanguageDetector(nullptr) { Reset(); }
+  virtual      ~nsCJKDetector() {}
+
+  const char*   GetLanguage();
+  nsDetectState HandleData(const int* codepoints, PRUint32 cpLen);
+  float         GetConfidence(void);
+  void          Reset(void);
+
+protected:
+  /* Chinese characters (Kanji in Japanese) */
+  PRUint32    mHanziChar;
+  /* Korean alphabet and syllabaries */
+  PRUint32    mHangulChar;
+  /* Hiragana and Katakana (Japanese) */
+  PRUint32    mKanaChar;
+
+  const char* language;
+  float       confidence;
+
+private:
+
+  void ComputeConfidence(void);
+};
+
+#endif /* nsCJKDetector_h__ */
diff --git a/src/nsMBCSGroupProber.cpp b/src/nsMBCSGroupProber.cpp
index 1b99da1..f19ec25 100644
--- a/src/nsMBCSGroupProber.cpp
+++ b/src/nsMBCSGroupProber.cpp
@@ -38,6 +38,7 @@
  * ***** END LICENSE BLOCK ***** */
 #include <stdio.h>
 
+#include "nsCJKDetector.h"
 #include "nsMBCSGroupProber.h"
 #include "nsUniversalDetector.h"
 
@@ -106,7 +107,7 @@ nsMBCSGroupProber::nsMBCSGroupProber(PRUint32 aLanguageFilter)
       langDetectors[i][j++] = new nsLanguageDetector(&HungarianModel);
       langDetectors[i][j++] = new nsLanguageDetector(&IrishModel);
       langDetectors[i][j++] = new nsLanguageDetector(&ItalianModel);
-      langDetectors[i][j++] = new nsLanguageDetector(&KoreanModel);
+      //langDetectors[i][j++] = new nsLanguageDetector(&KoreanModel);
       langDetectors[i][j++] = new nsLanguageDetector(&LatvianModel);
       langDetectors[i][j++] = new nsLanguageDetector(&LithuanianModel);
       langDetectors[i][j++] = new nsLanguageDetector(&MalteseModel);
@@ -120,6 +121,7 @@ nsMBCSGroupProber::nsMBCSGroupProber(PRUint32 aLanguageFilter)
       langDetectors[i][j++] = new nsLanguageDetector(&ThaiModel);
       langDetectors[i][j++] = new nsLanguageDetector(&TurkishModel);
       langDetectors[i][j++] = new nsLanguageDetector(&VietnameseModel);
+      langDetectors[i][j++] = new nsCJKDetector();
     }
     else
     {