var childs=xmlDoc.documentElement.childNodes;
var options=new Array();
for(var i=0; i<childs.length; i++){
  if(!childs[i].tagName) continue;
  if(childs[i].tagName=='RV') var index=childs[i].firstChild.nodeValue;
  else if(childs[i].tagName=='RN') options[index]=childs[i].firstChild.nodeValue;
}