XML Namespace
XML namespaces attach a namespace URI to elements and attributes via xmlns:prefix="URI", avoiding name collisions between vocabularies.
Purpose
To qualify which vocabulary an element name belongs to in a mixed-vocabulary XML document, letting same-named elements coexist.
Mechanism
An xmlns:prefix="URI" declaration binds a prefix to a URI. The qualified name of an element or attribute is the pair (URI, localName). A default namespace xmlns="URI" applies to unprefixed elements.
Use cases
- SOAP mixed vocabularies
- SVG/MathML embedded in XHTML
- Composing XML standards