Axes

• XPath defines twelve axes along which an XPointer may search for nodes

• These depend on context to determine exactly what they point to.

• For instance, consider this location path:

  id("p6")/child::NAME

  It begins with the id() function that returns a node set containing the element with the ID type attribute whose value is p6. This provides a context node for the following location step along the relative child axis.

• Other axes include

  • ancestor

  • descendant

  • self

  • ancestor-or-self

  • descendant-or-self

  • attribute

• Each selects nodes from a particular subset of the nodes in the document. For instance, the following axis selects from nodes that come after the context node. The preceding axis selects from nodes that come before the context node.