2.2.13 [W3C-XSLT] Section 12.1, Multiple Source Documents

C0018:

The specification states:

 If there is an error retrieving the resource [an XML document specified by URI
 reference], then the XSLT processor may signal an error; if it does not signal an
 error, it must recover by returning an empty node-set. One possible kind of
 retrieval error is that the XSLT processor does not support the URI scheme used by
 the URI. An XSLT processor is not required to support any particular URI schemes.
 The documentation for an XSLT processor should specify which URI schemes the XSLT
 processor supports.

MSXML3 and MSXML6

If there is an error retrieving the resource, the XSLT processor signals an error and does not return an empty node set.

The XSLT processor supports the following URI schemes:

file

      Local file

ftp

      File Transfer Protocol

gopher

      Gopher protocol

http

      Hypertext Transfer Protocol

mailto

      Electronic mail address

Note    In response to a mailto request, the XSLT processor first requests privilege to display a New Mail window using the default mail sender. The window is displayed only if privilege is granted.