Modularization of XHTML in RELAX NG

This directory contains an implementataion in RELAX NG of the modularization of XHTML specified by the Modularization of XHTML Recommendation.

The RELAX NG patterns have not been mechanically derived from the DTDs. Rather, they have been hand-crafted so as to produce good quality RELAX NG patterns. However, they may well contain bugs.

The modules directory contains all the modules; xhtml-basic.rng uses the modules to implement XHTML Basic; xhtml-strict.rng uses the modules to implement XHTML 1.0 strict; xhtml.rng uses the modules to implement the union of XHTML 1.0 transitional and XHTML 1.0 frameset. You can download everything as a zip file. To create a custom version of XHTML, simply copy xhtml.rng and delete the inclusions of the modules that you do not want.

The biggest difference between the RELAX NG implementation and the DTD implementation is that the RELAX NG implementation does not require you to create a model module specific to the combination of XHTML modules you are using. Instead, simply include the modules you want. The modules take care of redefining the content models appropriately.

Note also the following differences:

• The frames module is used instead of the struct module, rather than in addition to it.
• In the frames module, the frameset element does not restrict the optional noframes element to follow all the other child elements. XHTML Modularization is inconsistent with both HTML 4.0 and XHTML 1.0 here.
• In the basic tables abstract module, the table element does not have a width attribute. The XHTML Rec is ambiguous here: the abstract module has the attribute, but the DTD does not.
• The object and applet modules takes advantage of RELAX NG's absence of restrictions on mixed content to enforce the requirement that params precede other content.