While a well-formed document is well-formed because it follows rules defined by the XML spec, a valid document is valid because it matches its document type definition (DTD). The DTD is the grammar ...

Have you ever played the “spot the development platform” game? In my version of it, points are awarded to players who correctly guess what programming language an application is written in, simply by ...

SGML (standard generalized markup language) is a standard for how to specify a document markup language or tag set. Such a specification is itself a document type definition (DTD). SGML is not in ...

THE GOOD NEWS is that Office 11 supports XML Schema. The bad news is that XML Schema has been described even by XML experts as “confusing,” “impenetrable,” “fuzzy,” and “as user-friendly as a stick in ...

Nearly everyone is talking about XML (Extensible Markup Language) these days. But few understand what it's really all about. XML's proponents claim it will cure everything that's wrong with HTML and ...