It is a free,open-source chm viewer written in C++ for Linux and Windows systems
EditBy: Kchmviewer is a free, open-source chm (MS HTML Help file format) viewer written in C++ for Unix, Mac and Windows systems. Unlike most existing CHM viewers for Unix, it uses Trolltech Qt widget library, and could optionally be compiled for better KDE integration. It does not require KDE, but may be compiled with full KDE support, including KDE widgets and KIO/KHTML.

Here is the full list of kchmviewer features:

- Standalone viewer, depends on Qt only. Does not require KDE, but can use it for extra functionality if configured with --with-kde. Does not require or use GNOME, gtk or wxWindows libraries.

- When compiled with KDE support uses a KIO slave, KHTML, KDE widgets and DCOP support.

- Safe and harmless. In Qt mode ignores JavaScript, and warns you before opening an external web page, or switching to another help file. While using KHTML, executing Javascript is an option.

- Supports tab browsing.

- Correctly detects and shows encoding of any valid chm file.

- Correctly shows non-English chm files, including Cyrillic, Chinese, Japanese and others.

- Correctly searches in non-English chm files even using chm built-in search index (but does even better with its own search engine).

- Etc. you can free download Kchmviewer for Linux 4.1 now.