HTML Help File Type Chart

HTML Help involves many different components, each of which requires a different file type with its own extension and special requirements. For each of the possible HTML Help components, the following table shows: the appropriate Extension in HTML Help (plus the extension of the Windows Help counterpart, if any); the name generally used to refer to that File Type; the tool or application that the component is Created in; and the Purpose & Use of that component.

For additional information about using these file types, consult the Process Overview.

Extension	File Type	Created in	Purpose & Use
`.chm (.hlp)`	compiled help file	HTML Help Workshop	contains all elements of the Help system (text, graphics, styles, scripts, contents, index, search) in a single compressed file that is distributed to the end user
`.css`	cascading style sheet	HTML editor, specialized CSS tool, or text editor (Notepad)	contains formatting definitions (fonts, sizes, colors, backgrounds). The`.css` extension is used for an external file that HTML files link to. (Stylesheets may also be embedded in individual HTML files.)
`.hhc (.cnt)`	help contents file	HTML Help Workshop or text editor (Notepad)	contains table of contents for the project; in modular project, may contain references to external `.hhc` files
`.hhk`	help index file	HTML Help Workshop or text editor (Notepad)	contains a specific list of indexed terms and their associated files. Does not include either Alinks or Klinks, though Klinks may be merged into the index during compilation.
`.hhp (.hjp)`	help project file	HTML Help Workshop or text editor (Notepad)	contains information about the project, including window definitions, included files, compiler & compatibility options, default page
`.htm .html (.rtf)`	web page	HTML editor, HTML Help Workshop, or text editor	contains the actual text and graphics of the project’s Help pages
`.js`	JavaScript or JScript file	scripting tool or text editor (Notepad)	contains scripts that provide dynamic presentations or interactivity with the user. The `.js` extension is used for an external file that HTML files link to. (Scripts may also be embedded in individual HTML files.)