MSXML is still only DOM-1 compliant

If you use DOM calls to manipulate XML documents returned with XMLHttpRequest object (and who doesn't), you'll be sooner or later highly upset when the code you've tested on Firefox or Opera fails in IE (including IE7). The reason - Microsoft still did not implement Node.getElementById function. So here's the "replacement":

function getDomById(e,id) {
  if (e.getElementById) { return e.getElementById(id); }
  if (e.documentElement) e = e.documentElement;
  
  var cn = e.childNodes;
  for (var i = 0 ; i != cn.length; i++) {
    var n = cn[i]; 
    if (n.nodeType == 1) {
      if (n.getAttribute("id") == id) return n ;
    }
  }
  for (var i = 0 ; i != cn.length; i++) {
    var n = cn[i]; 
    if (n.nodeType == 1) {
      var result = getDomById(n,id); if (result) return result;
    }
  }
  return false;
}

Note: The procedure is doing breadth-first search as I was looking for IDs that were pretty high in the hierarchy of trees with many branches.