code: function (elem)
      {
          var impNode;
          var xmlGen = Strophe.xmlGenerator();
          try {
              impNode = (xmlGen.importNode !== undefined);
          }
          catch (e) {
              impNode = false;
          }
          var newElem = impNode ?
                        xmlGen.importNode(elem, true) :
                        Strophe.copyElement(elem);
          this.node.appendChild(newElem);
          this.node = newElem;
          return this;
      }
docs: Function: cnode
  Add a child to the current element and make it the new current
  element.
  
  This function is the same as c() except that instead of using a
  name and an attributes object to create the child it uses an
  existing DOM element object.
  
  Parameters:
  (XMLElement) elem - A DOM element.
  
  Returns:
  The Strophe.Builder object.