原文：https://blog.csdn.net/csdnluolei/article/details/84307668

方法一

Date.prototype.format = function(format)
{
 var o = {
 "M+" : this.getMonth()+1, //month
 "d+" : this.getDate(),    //day
 "h+" : this.getHours(),   //hour
 "m+" : this.getMinutes(), //minute
 "s+" : this.getSeconds(), //second
 "q+" : Math.floor((this.getMonth()+3)/3),  //quarter
 "S" : this.getMilliseconds() //millisecond
 }
 if(/(y+)/.test(format)) format=format.replace(RegExp.$1,
 (this.getFullYear()+"").substr(4 - RegExp.$1.length));
 for(var k in o)if(new RegExp("("+ k +")").test(format))
 format = format.replace(RegExp.$1,
 RegExp.$1.length==1 ? o[k] :
 ("00"+ o[k]).substr((""+ o[k]).length));
 return format;
}
 
//日期格式化
var d = new Date();
var useDate = d.format('yyyy-MM-dd');
var useDate2 = d.format('yyyy-MM-dd hh:mm:ss');

方法二

  var Dates = new Date();
  var Y = Dates.getFullYear();
  var M = Dates.getMonth() + 1;
  var D = Dates.getDate();
  var times = Y + (M < 10 ? "-0" : "-") + M + (D < 10 ? "-0" : "-") + D;
  alert(times);