FormCalc var loop

Hi,

I have some question related FormCalc for expression.

I'm trying to loop trought variable with no luck.

Code:

//take list of user names

var userName= xfa.resolveNodes(concat("$record.empls.empl.[fg_code==""",fgCode,"""].empl_name"))

//loop thriught it

var len = userName.length

for i=0 upto len-1 step 1 do
         xfa.host.messageBox(userName.nodes.item(i))
endfor

not working, i'm getting messages that i can't access properti length or item.

Hoe can I loop trought FormCalc variable?

Thanks in advance.