# fn:base-uri - XPath XQuery Reference

Returns the base URI of a node.deterministiccontext-dependentfocus-dependentdeterministiccontext-independentfocus-independentThe zero-argument version of the function returns the base URI of the context node: it
            is equivalent to calling fn:base-uri(.).The single-argument version of the function behaves as follows:If $arg is the empty sequence, the function returns the empty
               sequence.Otherwise, the function returns the value of the dm:base-uri accessor
               applied to the node $arg. This accessor is defined, for each kind of
               node, in the XDM specification (See ).As explained in XDM, document, element and processing-instruction nodes have a
            base-uri property which may be empty. The base-uri property for all other node kinds is
            the empty sequence. The dm:base-uri accessor returns the base-uri property of a node if
            it exists and is non-empty; otherwise it returns the result of applying the dm:base-uri
            accessor to its parent, recursively. If the node does not have a parent, or if the
            recursive ascent up the ancestor chain encounters a parentless node whose base-uri
            property is empty, the empty sequence is returned. In the case of namespace nodes,
            however, the result is always an empty sequence — it does not depend on the base URI of
            the parent element.See also fn:static-base-uri.The following errors may be raised when $arg is omitted:If the context item is absent,
                  dynamic error If the context item is not a node, type error .