js code to implement date picker

/* JS代码部分 */
 3 const date = new Date()
const years = []
const months = []
const days = []
const hours = []
const minutes = []
var thisMon = date.getMonth();
var thisDay = date.getDate();

for (let i = 2017; i <= date.getFullYear() + 1; i++) {
  years.push(i)
}

for (let i = date.getMonth(); i <= 11; i++) {
  var k = i;
  if (0 <= i && i < 9) {
    k = "0" + (i + 1);
  } else {
    k = (i + 1);
  }
  months.push(k)
}
if (0 <= thisMon && thisMon < 9) {
  thisMon = "0" + (thisMon + 1);
} else {
  thisMon = (thisMon + 1);
}
if (0 <= thisDay && thisDay < 10) {
  thisDay = "0" + thisDay;
}

var totalDay = mGetDate(date.getFullYear(), thisMon);
for (let i = 1; i <= 31; i++) {
  var k = i;
  if (0 <= i && i < 10) {
    k = "0" + i
  }
  days.push(k)
}

for (let i = 0; i <= 23; i++) {
  var k = i;
  if (0 <= i && i < 10) {
    k = "0" + i
  }
  hours.push(k)
}
for (let i = 0; i <= 59; i++) {
  var k = i;
  if (0 <= i && i < 10) {
    k = "0" + i
  }
  minutes.push(k)
}
function mGetDate(year, month) {
  var d = new Date(year, month, 0);
  return d.getDate();
}
Page({
  data: {
    years: years,
    year: date.getFullYear(),
    months: months,
    month: thisMon,
    days: days,
    day: thisDay,
    value: [1, thisMon - 1, thisDay - 1, 0, 0],
    hours: hours,
    hour: "00",
    minutes: minutes,
    minute: "00",
  },
  bindChange: function (e) {
    const val = e.detail.value
    this.setData({
      year: this.data.years[val[0]],
      month: this.data.months[val[1]],
      day: this.data.days[val[2]],
      hour: this.data.hours[val[3]],
      minute: this.data.minutes[val[4]],
    })
    var totalDay = mGetDate(this.data.year, this.data.month);
    var changeDate = [];
    for (let i = 1; i <= totalDay; i++) {
      var k = i;
      if (0 <= i && i < 10) {
        k = "0" + i
      }
      changeDate.push(k)
    }
    this.setData({
      days: changeDate
    })
  },

})





/* css代码部分 */
.time-title{
  float:left;
  width:20%;
  text-align:center;
  color:#45BCE8;
}
.picker-text{
  text-align:center;
}
/*mask*/
.time_screens {
 width: 100%;
 position: fixed;
 bottom: 0;
 left: 0;
 z-index: 1000;
 opacity: 0.5;
 overflow: hidden;
}


/* html代码部分 */
  <view class="time_screens">
    <view style="text-align:center;color:#45BCE8">{{year}}-{{month}}-{{day}}
      <label style="float:left;margin-left:30px;">取消</label>
      <label style="float:right;margin-right:30px;">确定</label>
    </view>
    <view style="border-top:1px solid #45BCE8;height:25px;font-size:14px;">
    </view>
    <picker-view indicator-style="height: 50px;" style="width: 100%; height: 300px;" value="{{value}}" bindchange="bindChange">
      <picker-view-column class="picker-text">
        <view wx:for="{{years}}" style="line-height: 50px">{{item}}年</view>
      </picker-view-column>
      <picker-view-column class="picker-text">
        <view wx:for="{{months}}" style="line-height: 50px">{{item}}月</view>
      </picker-view-column>
      <picker-view-column class="picker-text">
        <view wx:for="{{days}}" style="line-height: 50px">{{item}}日</view>
      </picker-view-column>

    </picker-view>
  </view>

/* Json */
{
  "navigationBarTitleText": "XXXX"
}