The XHTML transform was the first transform created for the DITA Open Toolkit; it converts DITA topics into XHTML documents. In addition to the XHTML output, this transform also returns a simple table of contents file named index.html, which is based on the structure of the input map file.
XHTML output is always associated with the default DITA-OT CSS stylesheet "commonltr.css" (or "commonrtl.css" for right-to-left languages). Parameters are available to override the default CSS styling.
To run the default XHTML transform, set the transform type parameter to "xhtml". Many of the other transform types run the same conversion to XHTML, followed by additional routines to create new navigation files.