Firefox support for document-uri of root xml

My basic question is there any way to get the browser uri inside XSLT
when using Firefox?

In other words any way to get the equivalent of the XPath 2.0 document-
uri for the root xml document?

To be clear

If the user of Firefox has entered into the web address

http://arsmc.org/documents/canobie_series.xml?page=1

I want to be able to access the string value or something equivalent
to the uri the user sees namely

http://arsmc.org/documents/canobie_series.xml?page=1

Microsoft allows one to drop into javascript inside XSLT to get this
information. Does Firefox support any extension to XSLT 1.0 or XPath
1.0 which allows one to get this browser uri during XSLT processing?

This seems like a very useful and simple extension to support since
clearly Firefox has access to this information and it is static during
the processing of the XML by XSLT.