A revolutionary new technology for the rapidly expanding world of e-commerce, XUL (XML User Interface Language) is an XML-based user interface language that gives Web developers control over all aspects of the Web interface. Featuring two tutorials on programming with XUL, this book shows developers how to use basic XUL elements to build a sample interface for an e-commerce site, then goes on to explore more sophisticated applications by creating an information portal inside an application. Readers will find expert tips and advice on how to get started writing XUL code as well as how to extend it into Java and other non-Netscape interfaces.