XML in a Nutshell, 3rd Edition

Node Tests

Each location step has at least an axis and a node test. The node test further refines the nodes selected by the location step. In an unabbreviated location step, a double colon (::) separates the axis from the node test. There are seven kinds of node tests:

name

An XML name matches all elements with the same name. However, along the attribute axis it matches all attributes with the same name instead; along the namespace axis it matches all namespaces with that prefix. As usual, if the element or attribute name is prefixed, only the URI to which the prefix is mapped matters, not the prefix itself. Unprefixed names always match nodes in no namespace, never names in the default namespace.

prefix :*

Along most axes, this node test matches all element nodes whose namespace URIs are the same as the namespace URI to which this prefix is mapped, regardless of name. However, along the attribute axis, this node test matches all attribute nodes whose namespace URIs are the same as the namespace URI to which this prefix is mapped.

comment( )

This matches all comment nodes.

text( )

This matches all text nodes. Each text node is a maximum contiguous run of text between other types of nodes.

processing-instruction( )processing-instruction('target')

With no arguments, this node test selects all processing instructions. With a single string argument, it selects all processing instructions that have the specified target.

node( )

This node test selects all nodes, regardless of type: attribute, namespace, ...