XSLT

The Built-in Template Rules
There are seven kinds of nodes in an XML document:

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the root node, element nodes, attribute nodes, text nodes, comment nodes, processing instruction nodes, and namespace nodes.

XSLT provides a default built-in template rule for each of these seven kinds of nodes that says what to do with that node if the stylesheet author has not provided more specific instructions. These rules use special wildcard patterns to match all nodes of a given type. Together these template rules have major effects on which nodes are activated when.

by default, the XSLT processor never reaches attribute nodes and, therefore, never outputs the value of an attribute. Attribute values are output according to this template only if a specific rule applies templates to them, and none of the default rules do this because attributes are not considered to be children of their parents. In other words, if element E has an attribute A, then E is the parent of A, but A is not the child of E. (The biological metaphor breaks down here.) Applying templates to the children of an element with <xsl:apply-templates/> does not apply templates to attributes of the element. To do that, the xsl:apply-templates element must have a match pattern specifically selecting attributes.

Only attribute and namespace nodes are not children of their parents.