adding a DTD file

To be able to localize all that text, we need to declare general (text) entities for all locale sensitive resources in an external DTD (Document Type Definition) subset and use an XML entity reference, "&entity_name;", to reference them.
The DTD file is placed in an appropriate "locale" directory of our project.

Sample XUL: openLocation.xul

<?xml version="1.0"?>
<!DOCTYPE dialog SYSTEM "chrome://communicator/locale/openLocation.dtd">
<dialog ... title="&caption.label;">

Sample DTD: openLocation.dtd

<!ENTITY caption.label "Mozilla - Open Web Location">
<!ENTITY enter.label "Enter the web location (URL), or specify the local file you would like to open:">