new Date()
年月日时分秒
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<script>
//object
var body = document.body;
setInterval(fnTime, 1000);
fnTime();
function fnTime() {
var myTime = new Date();
//number
var iYear = myTime.getFullYear();//年
var iMonth = myTime.getMonth() + 1;//月
var iDate = myTime.getDate();//日
var iWeek = myTime.getDay();//星期
var iHours = myTime.getHours();//时
var iMin = myTime.getMinutes();//分
var iSec = myTime.getSeconds();//秒
var str = "";
if (iWeek == 0) { iWeek = "星期日" }
if (iWeek == 1) { iWeek = "星期一" }
if (iWeek == 2) { iWeek = "星期二" }
if (iWeek == 3) { iWeek = "星期三" }
if (iWeek == 4) { iWeek = "星期四" }
if (iWeek == 5) { iWeek = "星期五" }
if (iWeek == 6) { iWeek = "星期六" }
str = iYear + "年" + iMonth + "月" + iDate + "日 " + iWeek + "" + fn1(iHours) + ":" + fn1(iMin) + ":" + fn1(iSec);
body.innerHTML = str;
}
function fn1(n) {
return n < 10 ? "0" + n : "" + n;
}
</script>
</body>
</html>
倒计时
Math.floor(t/86400)//天
Math.floor(t%86400/3600)//时
Math.floor(t%86400%3600/60)//分
t%60//秒
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<script>
var iNow=new Date();
var iNew=new Date(2017,8,28,15,19,00);//未来时间
// var iNew=new Date("September 28,2017 15:19:00");//字符串
var t=Math.floor((iNew-iNow)/1000);//毫秒=>秒
// Math.floor(t/86400)//天
// Math.floor(t%86400/3600)//时
// Math.floor(t%86400%3600/60)//分
// t%60//秒
var str=Math.floor(t/86400)+"天"+Math.floor(t%86400/3600)+"时"+Math.floor(t%86400%3600/60)+"分"+t%60+"秒";
alert(str);
</script>
</body>
</html>