Using position predicate in XPath string within selec

Hi !

Does anybody know why I can't write something like this :

Set objNode= objXML.selectSingleNode("foo[3]")

(no node matched)

Whereas objNode= objXML.selectSingleNode("foo") works fine

foo[3] is the abreviation for foo[position()=3]

position() is a function, would that means that function are not allowed in
Xpath string within selectSingleNode

I've also tried with SelectNodes method, but I still have the same problem

I use ASP with DOM and my parser is MSXML3

Has anybody an explanation for this,

In advance Thanks,

Regards,

Matthieu.