wx-if 结合 new Date() 实现条件渲染

   : function () {
    var timeDay = new Date().getDate();
    var timeMonth = new Date().getMonth()
    var timeYear = new Date().getFullYear();

    this.setData({
      timeDay: timeDay,
      timeMonth: timeMonth + 1, 
      timeYear: timeYear,
    });  
  },

<!-- 活动时间 -->
<view wx-if="{{timeYear === 2018 && timeMonth === 11 && timeDay === 9}}" class="newBg" hidden="{{hiddenName}}">
  <image src='https://xxx-xxxxxx.cos.ap-chengdu.myqcloud.com/11bg-3.png'></image>
  <view class="close" catchtap='closeBg'>关闭 {{sec}}</view>
</view>

<view wx-if="{{timeYear === 2018 && timeMonth === 11 && timeDay === 10}}" class="newBg" hidden="{{hiddenName}}">
  <image src='https://xxx-xxxxxx.cos.ap-chengdu.myqcloud.com/11bg-2.png'></image>
  <view class="close" catchtap='closeBg'>关闭 {{sec}}</view>
</view>

<view wx-if="{{timeYear === 2018 && timeMonth === 11 && timeDay === 11}}">
  <image src='https://xxx-xxxxxx.cos.ap-chengdu.myqcloud.com/11bg-1.png'></image>
  <view class="close" catchtap='closeBg'>关闭 {{sec}}</view>
</view>