Unless in some strange framework operating on a planet far far away, Javascript is not executed during an XSLT transformation.

Well, the presence of bsj.jar indicates he intends to use extension
functions written in JavaScript in his style sheet. I have to say that
I can't imagine why people insist in doing this, they almost invariably
shoot themself in the foot at first.

Xalan, which has no Javascript support TMK)

Xalan can use any script language for wich a Java based interpreter
exists through BSF. I've even seen a Perl binding.