# File lib/html/rexml-nodepath.rb, line 24
    def child_index
      return "" unless parent
      siblings = parent.to_a.select do |node| 
        node.kind_of? Element and node.expanded_name == self.expanded_name
      end
      return "" if siblings.size < 2
      "[" + (siblings.index(self)+1).to_s + "]"
    end