So far, the plain text in the documents we've looked at in this chapter has been confined to the deepest elements in the document—that is, to elements that enclose no child elements, just text. However, as you know, you can also create elements that support mixed content—both text and other elements. You can create mixed-content elements with schemas as well as DTDs. In these elements, character data can appear at the same level as child elements.
Here's an example document that shows what mixed-content elements look like using the elements we've declared in ch05_07.xsd. In this case, I'm creating a new element named <reminder> that encloses a reminder letter to a book borrower reminding him to return a book: