code: function(cmd) {
              var target = document.createElement("div");
              target.setAttribute('id', placeholderId);
  
              if (iframe) {
                  _msgDispatcher && _msgDispatcher.unbindEvents();
                  _detachMouseEvents();
                  iframe.parentNode && iframe.parentNode.replaceChild(target, iframe);
              }
          }
docs: /*
  cmd = {
  command: 'commandName',
  data: <command specific data>
  }