XML Namespace - Namespace Undeclaration

Namespace Undeclaration

When an element carries the attribute xmlns="", the default namespace for that element and its descendants reverts to "no namespace": that is, unprefixed names are considered not to be in any namespace.

XML Namespaces 1.1 also introduces the option to undeclare other namespace prefixes. For example, if the attribute xmlns:p="" appears on an element, the namespace prefix p is no longer in scope (and therefore cannot be used) on that element or on its descendants, unless reintroduced by another namespace declaration.