docs: function(url, params, onsuccess, onfail) {
      // url中包含 get 参数和 params 合并
      if (_typeof(params) == 'object') params = _params_2_url(params);
      else params = '';
  
      if (params) url = url + '?' + params;
      return request('GET', url, '', onsuccess, onfail);
    }