code: function(o) {
                  try {
                      return ( o                     && // o is something
                               typeof o !== "string" && // o is not a string
                               o.length              && // o is indexed
                               !o.tagName            && // o is not an HTML element
                               !o.alert              && // o is not a window
                               typeof o[0] !== "undefined" );
                  } catch(ex) {
                      YAHOO.log("node access error (xframe?)", "warn");
                      return false;
                  }
  
              }
docs: We want to be able to use getElementsByTagName as a collection
  to attach a group of events to.  Unfortunately, different
  browsers return different types of collections.  This function
  tests to determine if the object is array-like.  It will also
  fail if the object is an array, but is empty.
  @method _isValidCollection
  @param o the object to test
  @return {boolean} true if the object is array-like and populated
  @static
  @private