There are two solutions to your problem:

1. Avoid the additional select attribute, so that the position() in the span "sees" the position of the div:

<div select="item" values="class:ext-if(position() mod 2 = 0,'white','green')"> <span values"id:position()" content="name"></span> </div>

2. Remember the position() of the div in a variable and use the variable in the span:

<div select="item" values="class:ext-if(position() mod 2 = 0,'white','green');$position:position()"> <span select="name" values"id:$position" content="."></span> </div>

The XPath function position() returns the position of the current node in the current node set. Every select attribute establishes a context with a new node set in which XPath expressions are evaluated.