XPath, count function

Hi!

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

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

count(//*[@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