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ChmFox: Firefox Extension for Viewing CHM files

ChmFox is a Firefox extension which brings the best CHM file reading experience to all platforms. CHM file could be viewed directly in Firefox using this extension under Windows, Mac and Linux.


  1. Download and install ChmFox
  2. After installation, restart Firefox to make it work
  3. Open CHM files through Menu -> File -> Open
  4. You could make firefox the default program for opening CHM file, after doing that, just double click CHM files and enjoy ChmFox
  5. There's a sidebar for the CHM file content/index, you could use hotkey Ctrl+Alt+m (or Command+Option+m under Mac) to turn it on/off
  6. ChmFox remembers and jumps to the last reading position when re-open CHM file and you could always bookmark as many CHM pages as you like using Firefox's build-in bookmark function
  7. Zoom the page by Ctrl + / Ctrl -, just as normal web page. ChmFox remembers the page zoom level per CHM file

Build It Yourself

ChmFox currently support following platforms

If your platform is not supported yet, you could always build it yourself:

  1. Download source code
  2. A C compiler and SCons build system are required on your system to build the source code
  3. Add new platform directive in file ./chrome.manifest
  4. Run the command "scons xpi" under the source tree, if everything is OK, you could find the final xpi file under ./build directory
  5. Drop author an email to help add this platform to the offical build so that others could benifit as well


ChmFox is open sourced under MPL 1.1/GPL 2.0/LGPL 2.1

Help make it better

If you like ChmFox and want to help make it better, you could

Download files:


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