docs: function getInstanceId(qualifier, successCallback) {
          // If the first argument is a function, assume that is the callback and that the caller
          // wants the session id
          if(typeof qualifier === 'function') {
              successCallback = qualifier;
              qualifier = null;
          }
          return neon.util.ajaxUtils.doGet(
              neon.serviceUrl('widgetservice', 'instanceid', buildInstanceIdQueryString(qualifier)), {
                  success: function(instanceId) {
                      if(!instanceId) {
                          return;
                      }
                      if(successCallback && typeof successCallback === 'function') {
                          successCallback(instanceId);
                      }
                  },
                  error: function() {
                  }
              }
          );
      }