In the previous article in this series, we put together the main interface file. Before you can see how it will look, however, you need to describe it in a language that Mozilla can understand. This article will show you how to create the appropriate RDF file, register it with Mozilla's chrome directory, and in general get to the point where you can see the fruits of your labors over the previous two articles.
Back to XUL: Uniting XUL and RDF - Linking the DTD to the XUL File (Page 3 of 4 )
As the DTD file is technically a resource, we are going to describe it with another contents.rdf file. In a new text file, begin in the normal way with the XML declaration and the opening RDF:RDF statement, complete with namespaces:
This file should be saved in the same location as the locale file it is describing. We can now register this, much in the same way as the main interface file was registered. Again, find the installed-chrome.txt file and add the following line to the bottom of the file:
Press return at the end, save and close the file, and as you are in the Mozilla/chrome directory, delete chrome.rdf. Again, if this is done correctly, information relating to this locale will appear in the chrome.rdf file once it is recreated by Mozilla.
XML 
Skinning Your Custom XUL Applications
