XML Schemas will take over from DTDs as the primary method of defining XML data. Some of the most powerful reasons for using XML Schemas are their ability to: validate much more powerfully with extended constraint mechanisms; the ability to create your own datatypes; dynamically bind instance documents to schemas at run time; be used with existing XML tools as they are written in XML syntax; support namespaces; and merge schemas into one.
Jon Duckett has been designing and building web sites for over a decade, working with global brands, and has authored and co-authored over a dozen books on web design, programming, usability and accessibility. He has curated conferences about web programming and has been a web strategy consultant, often coding front ends for projects and designing architectures for back end programming. He is the author of the best-selling, HTML & CSS: Design and Build Websites and JavaScript & jQuery: Interactive Front-End Web Development.