时间与倒计时

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>