y defining modules and
specifying a mechanism for combining these modules. This
mechanism will enable the extension and sub-setting of XHTML 1.0
in a uniform way through the definition of new modules.</p>

<h2><a name="mods" id="mods">6.1 Modularizing HTML</a></h2>

<p>As the use of XHTML moves from the traditional desktop user
agents to other platforms, it is clear that not all of the XHTML
elements will be required on all platforms. For example a hand
held device or a cell-phone may only support a subset 