KeyHelp
KeyHelp is a free ActiveX control that online help authors and programmers can use to enhance the capabilities of compiled Microsoft HTML Help systems and to control the behavior of HTML Help systems in a Windows application. It provides native HTML pop-ups, embedded windows, an auto-sizing secondary window, content-level Information Types, and and various script extensions. (2001-07-01)
The link address is: http://www.keyworks.net/keyhelp.htm