<script>
var countDownTime = {
init: function(a, b, c, d, e) {
this.t = a, this.d = b, this.h = c, this.m = d, this.s = e
},
start: function() {
var a = this;
setInterval(a.timer, 1e3)
},
timer: function(a) {
var b, c, d, e, f, g, h;
a = this.countDownTime, b = new Date, c = new Date(a.t), d = c.getTime() - b.getTime(), e = Math.floor(a.formatTime(d, "day")), f = Math.floor(a.formatTime(d, "hours")), g = Math.floor(a.formatTime(d, "minutes")), h = Math.floor(a.formatTime(d, "seconds")), a.d && (a.d.innerText = a.formatNumber(e)), a.h && (a.h.innerText = a.formatNumber(f)), a.m && (a.m.innerText = a.formatNumber(g)), a.s && (a.s.innerText = a.formatNumber(h))
},
formatNumber: function(a) {
if(a<=0){a=0}
return a = a.toString(), a[1] ? a : "0" + a
},
formatTime: function(a, b) {
switch (b) {
case "day":
return a / 1e3 / 60 / 60 / 24;
case "hours":
return a / 1e3 / 60 / 60 % 24;
case "minutes":
return a / 1e3 / 60 % 60;
case "seconds":
return a / 1e3 % 60
}
}
};
var day = document.getElementById('day');
var hours = document.getElementById('hours');
var minutes = document.getElementById('minutes');
var seconds = document.getElementById('seconds');
// 日 时 分 秒的dom对象
countDownTime.init('2021/01/21 14:20:00', day, hours, minutes, seconds);
countDownTime.start();
</script>
