v3退款接口提示普通商户不允许传sub_mch_id，关键是我根本没有传这个字段

H5支付看这个：https://pay.weixin.qq.com/wiki/doc/apiv3/apis/chapter3_3_9.shtml

URL:

https://api.mch.weixin.qq.com/v3/ecommerceefunds/apply

DATA:

{

    "amount": {

        "currency": "CNY",

        "refund": 10800,

        "total": 10800

    },

    "out_refund_no": "605363a33b1c605b130d6731",

    "out_trade_no": "604f111e3b1c606cf2602742",

    "reason": "商品已售完",

    "sp_appid": "wx56e82e6313f064a5",

    "sub_mchid": "1549457271"

}

你用错接口了，或者传参有误，把你请求参数和调用接口发出来