Compiled HTML definition filename extension
file format for distributing a collection of HTML
files, along with their associated images, sounds, etc., as a single compressed archive file.
Microsoft use this format for Windows
HTML Help files. Most chms include a project (.hhp) file listing the included files and basic settings, a contents (.hhc) file, an index (.hhk) file, html files, and, optionally, image files.
Users view chms with hh.exe, the HTML Help viewer installed with Internet Explorer
Filename extension: .chm.