|child||the children of the context node|
|descendant||all descendants (children, childrens children, ...)|
|parent||the parent (empty is at the root)|
|ancestor||all ancestors from the root to the parent|
|following-sibling||siblings to the right|
|preceding-sibling||siblings to the left|
|following||all following nodes in the document|
|preceding||all preceding nodes in the document|
|attribute||the attributes of the context node|
|namespace||namespace declarations in the context node|
|self||the context node itself|
|descendant-or-self||the union of descendant and self|
|ancestor-or-self||the union of ancestor and self|
Note that attributes and namespace declarations are considered a special kind of nodes.
Some of these axes assume a document ordering of the tree nodes. The ordering essentially corresponds to a left-to-right preorder traversal of the document tree.
The resulting sets are ordered intuitively, either forward (in document order)
or reverse (reverse document order).
For instance, following is a forward axis, and ancestor is a reverse axis.