URL http://e.vhall.com/api/vhallapi/v2/webinar/top-online-by-times 

返回形如{“code”:200,”msg”:“success”,”data”:[{“start_time”:“2016-09-21 15:05:21”,”num”:30},{“start_time”:“2016-09-07 13:58:27”,”num”:1}]}的json。data值的数据类型如下：

{
  "code": 200,
  "msg": "success",
  "data": [
    {
      "start_time": "2016-09-21 15:05:21",
      "num": 30
    },
    {
      "start_time": "2016-09-07 13:58:27",
      "num": 1
    }
  ]
}