"The biggest win for those looking to use XSLT in
Firefox is support for EXSLT, a set of XSLT extensions developed
and sanctioned by the XSLT community and supported in many other
XSLT processors. Firefox 3.0 adds support for a large subset of
EXSLT, starting with the node-set function, an important workaround
for XSLT 1.0's most severe limitation. EXSLT is organized into
modules, each of which defines several extension functions and
elements."