Compiled HTML help (also known as CHM help) has replaced WinHelp as the standard help format for Windows-based software applications.

A major problem with WinHelp is that the navigation is very poor from a usability perspective. Users cannot view both the Contents and the topics at the same time.

CHM online help overcomes this limitation. There is a standard tri-pane that shows Contents, Index and Find panes. These do not disappear when a user views the help pages (users have the option of hiding the panes).