nsURI

nsURI is an abbreviation for namespace URI, which is a unique identifier used in XML to define a namespace for a set of elements. A namespace is a mechanism that allows elements with the same name to be distinguished from each other in different documents.

In XML, an nsURI is typically specified in the XML document's root element using the prefix 'xmlns', which stands for XML name space. For example, a document might contain the following line: xmlns="http://www.example.com/mynamespace". The string "http://www.example.com/mynamespace" is an nsURI that uniquely identifies the namespace defined by the 'xmlns' attribute.

The nsURI is used to map an XML element's prefix to the element's tag name. The tag name of an element is determined by appending the local name of the element to the nsURI. The local name is the part of the element's tag name that follows the last colon character.

In addition to specifying the nsURI for an XML document, an XML processor may also identify the default namespace of a document. This can occur when an XML document is not explicitly assigned a namespace, but one is implied through the document's root element. The default namespace is not explicitly stated, but it is applied to elements in the document that do not have a specified namespace.

The use of nsURIs allows for the creation of reusable XML documents, as well as the ability to coexist with other namespace-defining documents. This enables developers to create complex structures, such as XML schema definitions, and to easily identify element origins within the context of a larger document. The standardization of naming conventions further enhances nsURI clarity, simplifying interactions between diverse software systems.