1. 效果图

2.实现代码

html
开始时间:
                <DatePicker type="date" placeholder="请选择日期" v-model="fromData.startDate" format="yyyy-MM-dd 00:00:00"
                            style="width:12%;margin-right:18px" @on-change="seachStartDate"></DatePicker>
                结束时间:
                <DatePicker type="date" placeholder="请选择日期" v-model="fromData.endDate" format="yyyy-MM-dd 23:59:59"
                            style="width:12%;margin-right:18px" @on-change="seachEndDate"></DatePicker>

js
 //设置默认日期
      setData(){
        let myData = new Date()
        let year = myData.getFullYear();
        let month = myData.getMonth()
        this.fromData.startDate = year+'-'+month+'-'+'01'//设置当前月开始日期
        this.fromData.endDate = this.getCurrentMonthLast();
      },
      // 获取当前月的最后一天
      getCurrentMonthLast() {
        let date = new Date();
        let currentMonth = date.getMonth();
        let nextMonth = ++currentMonth;
        let nextMonthFirstDay = new Date(date.getFullYear(), nextMonth, 1);
        let oneDay = 1000 * 60 * 60 * 24;
        **return util.formatDate(new Date(nextMonthFirstDay - oneDay), "yyyy-MM-dd 23:59:59");------格式化 日期工具类（就是拼接成字符串）**
      },

日期格式化工具类
util.formatDate = function (date, fmt) {
  if (/(y+)/.test(fmt)) {
    fmt = fmt.replace(RegExp.$1, (date.getFullYear() + '').substr(4 - RegExp.$1.length));
  }
  let o = {
    'M+': date.getMonth() + 1,
    'd+': date.getDate(),
    'h+': date.getHours(),
    'm+': date.getMinutes(),
    's+': date.getSeconds()
  };
  for (let k in o) {
    if (new RegExp(`(${k})`).test(fmt)) {
      let str = o[k] + '';
      fmt = fmt.replace(RegExp.$1, RegExp.$1.length === 1 ? str : util.padLeftZero(str));
    }
  }
  return fmt;
};