案例：

html:

  <view class="huanhang">
      <view class="fontBold">发起时间：</view>
      <view class="fontBold">   <picker class="getBusTime" mode="date" data-namesa="staDate" model:value="{{staDate?staDate:''}}" start="2020-01-01" end="2040-01-01" bindchange="bindFormDateChange">
            <view style="color: #000;" class="getBusTimeRight fontSize34">{{staDate}}</view>
          </picker></view>
    </view>

js：

data:{
		staDate:"选择时间",
},
	bindFormDateChange: function (e) {
	  this.setData({
	    [e.target.dataset.namesa]: e.detail.value
	  })
	},