Behind the Web services technology are several protocols: XML, XML Namespaces, XML Schema, SOAP, and WSDL. Some of these are formal W3C industry standards. Some, like WSDL, are just gaining widespread use without yet being codified in a standard.
XML is a W3C industry standard that provides a way to structure documents to provide relationships between the basic elements of the document. Elements can also have descriptive information called attributes. Elements can be composed of other elements, so they can have complex structure. Since such documents can be represented as text, XML can provide a platform-neutral way to represent data that is transmitted over a network. In particular, as text it can go safely out through a ...