关于小程序后台post不到数据的问题

 wx.request({
      url: host + "/card/create",
      header: { "Content-Type": "application/x-www-form-urlencoded" },
      method:"POST",

      data:{
        'card_no':e.detail.value['card_no']
      },
      success:function(result){
        wx.showToast({
          title: '请求成功！',
          icon: 'success',
          mask: true,
          duration: 2000
        })
      }