原生JS - 简单的时分秒倒计

效果图

代码片 直接copy就可以调用

<div id="timer"></div>

setInterval("leftTimer(2020,1,1,00,00,00)", 1000);
//倒计时
function leftTimer(year, month, day, hour, minute, second) {
var leftTime = (new Date(year, month - 1, day, hour, minute, second)) - (new Date()); //计算剩余的毫秒数
var days = parseInt(leftTime / 1000 / 60 / 60 / 24, 10); //计算剩余的天数
var hours = parseInt(leftTime / 1000 / 60 / 60 % 24, 10); //计算剩余的小时
var minutes = parseInt(leftTime / 1000 / 60 % 60, 10); //计算剩余的分钟
var seconds = parseInt(leftTime / 1000 % 60, 10); //计算剩余的秒数
days = checkTime(days);
hours = checkTime(hours);
minutes = checkTime(minutes);
seconds = checkTime(seconds);
document.getElementById("timer").innerHTML = days + "天" + hours + "小时" + minutes + "分" + seconds + "秒";
}

function checkTime(i) { //将0-9的数字前面加上0，例1变为01
if(i < 10) {
i = "0" + i;
}
return i;
}