Home >Online Product Documentation >Table of Contents >Specifying That An Element Can Contain One of a Group of Elements in DTDs
You might want to define an element that contains one element out of a group of elements. For example, you might want an InventoryNumber element to contain a book, magazine, or newsletter element.
When the XSLT processor validates an instance document against this DTD, it ensures that each instance of the new element you just defined contains exactly one of the referenced elements.
The tree representation for an InventoryNumber element that can contain a book, magazine, or newsletter element would look like the following: