text: Date.prototype.Format = function(fmt)
  {
      var o =
      {
          "M+" : this.getMonth() + 1, //月份
          "d+" : this.getDate(), //日
          "h+" : this.getHours(), //小时
          "m+" : this.getMinutes(), //分
          "s+" : this.getSeconds(), //秒
          "q+" : Math.floor((this.getMonth() + 3) / 3), //季度
          "S" : this.getMilliseconds() //毫秒
      };
      if (/(y+)/.test(fmt))
          fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
      for (var k in o)
          if (new RegExp("(" + k + ")").test(fmt))
              fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
      return fmt;
  }
  
  Date.prototype.addDays = function(d)
  {
      this.setDate(this.getDate() + d);
  };
  
  Date.prototype.addWeeks = function(w)
  {
      this.addDays(w * 7);
  };
  
  Date.prototype.addMonths= function(m)
  {
      var d = this.getDate();
      this.setMonth(this.getMonth() + m);
      if (this.getDate() < d)
          this.setDate(0);
  };
  
  Date.prototype.addYears = function(y)
  {
      var m = this.getMonth();
      this.setFullYear(this.getFullYear() + y);
      if (m < this.getMonth())
      {
          this.setDate(0);
      }
  };
  /*
   test
   var beginDate = "2016-08-31"
   var d1 = new Date(beginDate.replace(/\-/g, "\/"));
   d1.addDays(1);//加减日期操作
   alert(d1.Format("yyyy-MM-dd"));
  
   */
  