<div id="time"></div>
//獲取當前時間
	 function time() {
	 	var vWeek, vWeek_s, vDay;
	 	vWeek = ["星期天", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"];
	 	var date = new Date();
	 	year = date.getFullYear();
	 	month = date.getMonth() + 1;
     	day = date.getDate();
	 	hours = date.getHours();
	 	minutes = date.getMinutes();
	 	seconds = date.getSeconds();
	 	vWeek_s = date.getDay();
	 	document.getElementById("time").innerHTML = year + "年" + month + "月" + day + "日" + "\t" + hours + ":" + minutes +
	 		":" + seconds + "\t" + vWeek[vWeek_s];
	 };
	 setInterval("time()", 1000);

<div id="time"></div>
	let time = +new Date() //獲取當前時間戳
	function getFamtterTimer(time) { //傳入時間
		let date = new Date(time),
			Y = date.getFullYear(), // 年  
			M = date.getMonth() + 1, //月  
			D = date.getDate(), //日
			h = date.getHours(), //小時
			m = date.getMinutes(), //分鐘
			s = date.getSeconds(); //秒數(shù)
		document.getElementById("time").innerHTML = Y + '-' + getZero(M) + '-' + getZero(D) + ' ' + getZero(h) + ':' +
			getZero(m) + ':' + getZero(s);
	}
	function getZero(num) { // 個位數(shù)前補0
		if (parseInt(num) < 10) {
			num = '0' + num;
		}
		return num;
	}
	setInterval("getFamtterTimer(+new Date())", 1000);