XPath count function in JavaScript

Hi!

I wonder if its possible to use the count function of XPath in JavaScript 
instead of in XSL. I'm using MSXML.

I want to count the number of elements with the attribute fnamn="Tomas" and 
return the number:

count(//*[(_at_)fnamn="Tomas"])) 

Is it possible to use that expression in a function in JavaScript and return 
the number or do I have to use the selectNodes() and check the number of nodes 
in the nodeList?

/Tomas