To share XML data with others, you need to agree on a standard set of tag names and element attributes so that everyone in your group uses and applies tags the same way. One method for handling the sharing of XML data is to use a document type definition (DTD) file.

A DTD file provides a set of elements and attributes for members of the group to use. It also defines the rules about where elements can appear in the structural hierarchy. For example, the DTD file may require the Title element to be a child of the Story element because the title is supposed to appear inside the story; if you tag a title without tagging the story it appears in, the DTD file marks the Title element as invalid. You can search for and flag invalid structural errors in an InDesign file with a DTD file. This process is called validating.

To use a DTD file (if your document doesn’t already contain one), you load it into your document. This imports the element names from the DTD into the Tags panel. Others who have loaded the same DTD file have the same element names, which ensures that everyone in the group uses the same elements. The imported elements are locked, which means they can’t be deleted or renamed unless the DTD file is deleted from the document.

You may find that a DTD file created by a group or industry similar to yours includes tags and structures that meet your needs. For a current list of registered DTDs, visit www.xml.com/pub/rg/DTD_Repositories (English only).