Question

I have just started learning XPath and I am learning the language without the abbreviation first.

When a location path starts with the character ‘/’ the initial context node is forces to be the root node…

Sample xml from book:

<widget type="gadget">
    ...
</widget>

If I am supposed to write the XPath so I get the type attribute why do I have to write:

/child::widget/attribute::type

and not like this /attribute::type

Have I misunderstood something about the root node or? Because I thought ‘/’ and widget was the same…

Thank you

Answer 1

From http://www.w3.org/TR/xpath/#attribute-nodes

Each element node has an associated
set of attribute nodes; the element is
the parent of each of these attribute
nodes; however, an attribute node is
not a child of its parent element.

Only element nodes have attributes.

The root node is not an element. From http://www.w3.org/TR/xpath/#root-node

The root node is the root of the tree.
A root node does not occur except as
the root of the tree. The element node
for the document element is a child of
the root node. The root node also has
as children processing instruction and
comment nodes for processing
instructions and comments that occur
in the prolog and after the end of the
document element.

Thus you cannot select attributes of the root node like in /@* or /attribute::*

You ask:

Have I misunderstood something about
the root node or?

Yes. You should not confuse the root node (an abstraction) with the document element (some times also called the element root)