这种情况通常是因为在调用的时候，package参数有问题导致；

最可能的原因是：你在测试的权限不够不是开发者权限，获取小程序的oppid失败，缺少oppid所以获取不到prepay_id=''的值

wx.requestPayment中package参数必须是package:"prepay_id=wx21**************"，不然，会出现调用支付JSAPI缺少appid/total_fee；

正常情况下：

//{"appid":"wx0411fa6a39d61297","noncestr":"3reA4pSqGBPPryEL","package":"Sign=WXPay","partnerid":"1230636401","prepayid":"wx20170406175858b261288c050041764688","timestamp":1491472738,"sign":"4A50B67D47E062A1F3B739D76C683D37"}
//{"appid":"wx05a63e391546d945","noncestr":"Uvxaj0yZeE5uw0Wd","package":"Sign=WXPay","partnerid":"1460680002","prepayid":"wx201704221807041af49e25c90779187614","timestamp":1492855550,"sign":"08FB66188544D438DF074F815EB585DF"}

如下出现问题：