# HTML Help

The htmlhelp transformation generates HTML output, CSS files, and the control files that are needed to produce a Microsoft Compiled HTML Help (.chm) file.

In addition to the HTML output and CSS files, this transformation returns the following files, where mapname is the name of the root map.

File name | Description
--- | ---
mapname.hhc | Table of contents
mapname.hhk | Sorted index
mapname.hhp | HTML Help project file
mapname.chm | Compiled HTML Help file Note: The compiled file is only generated if the HTML Help Workshop is installed on the build system.

To run the HTML Help transformation, set the transtype parameter to htmlhelp, or pass the --format=htmlhelp option to the dita command line.

    dita --input=input-file --format=htmlhelp

where:

- input-file is the DITA map or DITA file that you want to process.