js判断时间格式不能超过30天

    let first = this.data.date  //开始时间    let second = e.detail.value  //结束时间    var data1 = Date.parse(first.replace(/-/g, "/"));    var data2 = Date.parse(second.replace(/-/g, "/"));    var datadiff = data2 - data1;    var time = 31 * 24 * 60 * 60 * 1000;    console.log(first.length)    console.log(second.length)    if (first.length > 0 && second.length > 0) {      if (datadiff < 0 || datadiff > time) {        wx.showToast({          title: '前后时间间隔不能大于31天',        icon: 'none',        duration: 2000,      })      this.setData({        date1: "结束时间"      })        return false;      }    }