[Element Traversal LC] access to element by index

[Daniel Glazman]

Hi,

1. congrats for this spec, I love it ; I can't count how many times in
   page or chrome script I am filtering out nodes that are not element
   nodes.

2. the ElementTraversal interface has a |childElementCount| attribute
   but misses access to an individual childElement based on its index.
   That would be really useful. Two solutions here :

   a. you remove the childElementCount attribute in favor of a

        readonly attribute NodeList    childElements;

      and that NodeList has all we need

   b. you add

        Node    item(in unsigned long index);

      but that is not really consistent with the existing way of
      querying list of nodes.

   My very strong preference goes to solution a.

Best,

</Daniel>