Date对象

var oDate = new Date();
//			console.log(oDate);
//			console.log(oDate.getFullYear());//年份
//			console.log(oDate.getMonth());//月份  0-11
//			console.log(oDate.getDate());//日期
//			console.log(oDate.getDay());//星期 0-6 0周日
//			console.log(oDate.getHours());//小时
//			console.log(oDate.getMinutes());//分钟
//			console.log(oDate.getSeconds());//秒
//			console.log(oDate.getTime());//1970年1月1日到现在的毫秒数
			
//			oDate.setFullYear(2020);
//			console.log(oDate.getFullYear());

　　

小例子，淘宝倒计时

<span></span>
		<i>时</i>
		<span></span>
		<i>分</i>
		<span></span>
		<i>秒</i>

　　

//			淘宝倒计时
			var oSpan = document.getElementsByTagName("span");
			var endDate = new Date("2016/2/17,12:00:00");
			var endTime = endDate.getTime();
			var time = setInterval(function(){
				var nowDate = new Date();
				var nowTime = nowDate.getTime();
				var timeLeft = endTime - nowTime;
//				console.log(timeLeft);
				var nowHour = Math.floor(timeLeft/(1000*60*60));
				var hourLeft = timeLeft%(1000*60*60);
				var nowMinute = Math.floor(hourLeft/(1000*60));
				var minuteLeft = hourLeft%(1000*60);
				var nowSecond = Math.floor(minuteLeft/1000);				
				oSpan[0].innerHTML = nowHour;
				oSpan[1].innerHTML = nowMinute;
				oSpan[2].innerHTML = nowSecond;
				if(timeLeft<=0){
					clearInterval(time);
					oSpan[0].innerHTML = 0;
					oSpan[1].innerHTML = 0;
					oSpan[2].innerHTML = 0;
				}
			},500)