javascript — Как я могу сделать сброс отсчета каждую ночь в 16:00

<?php if (new DateTime() < new DateTime( "16:00:00")) { ?>
<script type="text/javascript">
var check = 0;
/*set the countdown hour*/
var countDownTo = 16;
var CDown = function() {
this.state = 0; // if initialized
this.counts = []; // array holding countdown date objects and id to print to {d:new Date(2013,11,18,18,54,36), id:"countbox1"}
this.interval = null; // setInterval object
}

CDown.prototype = {
init: function() {
this.state = 1;
var self = this;
this.interval = window.setInterval(function() {
self.tick();
}, 1000);
},
add: function(date, id) {
this.counts.push({
d: date,
id: id
});
this.tick();
if (this.state == 0) this.init();
},
expire: function(idxs) {
for (var x in idxs) {
this.display(this.counts[idxs[x]], "Now!");
this.counts.splice(idxs[x], 1);
}

},
format: function(r) {
var out = "";
if (r.d != 0) {
out += r.d + " " + ((r.d == 1) ? "day" : "days") + ", ";
}
if (r.h != 0) {
out += r.h + " " + ((r.h == 1) ? "hour" : "hours") + ", ";
}
out += r.m + " " + ((r.m == 1) ? "min" : "mins") + ", ";
out += r.s + " " + ((r.s == 1) ? "sec" : "secs") + ", ";

return out.substr(0, out.length - 2);
},
math: function(work) {
var y = w = d = h = m = s = ms = 0;

ms = ("" + ((work % 1000) + 1000)).substr(1, 3);
work = Math.floor(work / 1000); //kill the "milliseconds" so just secs

y = Math.floor(work / 31536000); //years (no leapyear support)
w = Math.floor(work / 604800); //weeks
d = Math.floor(work / 86400); //days
work = work % 86400;

h = Math.floor(work / 3600); //hours
work = work % 3600;

m = Math.floor(work / 60); //minutes
work = work % 60;

s = Math.floor(work); //seconds



return {
y: y,
w: w,
d: d,
h: h,
m: m,
s: s,
ms: ms
};
},
tick: function() {
var now = (new Date()).getTime(),
expired = [],
cnt = 0,
amount = 0;

if (this.counts)
for (var idx = 0, n = this.counts.length; idx < n; ++idx) {
cnt = this.counts[idx];
amount = cnt.d.getTime() - now; //calc milliseconds between dates

// if time is already past
if (amount < 0) {
expired.push(idx);
}
// date is still good
else {
this.display(cnt, this.format(this.math(amount)));
}
}

// deal with any expired
if (expired.length > 0) this.expire(expired);

// if no active counts, stop updating
if (this.counts.length == 0) window.clearTimeout(this.interval);

},
display: function(cnt, msg) {
if (msg == `Now!`) {
check = 1;
msg = ``;
var cdown = new CDown();
var currentdate = new Date();
var year = currentdate.getFullYear();
var month = currentdate.getMonth();
var day = currentdate.getDate() + 1;
var currenthour = currentdate.getHours();
/*perform check here*/
if (countDownTo == 16) {
countDownTo = 0;
} else {
countDownTo = 16;
}
var hour = countDownTo;
var minute = 0;
var second = 0;
cdown.add(new Date(year, month, day, hour, minute, second), "countbox1");
} else {
check = 0;
}
if (countDownTo == 0) msg = ``;
document.getElementById(cnt.id).innerHTML = msg;


}
};

window.onload = function() {
var cdown = new CDown();
var currentdate = new Date();
var year = currentdate.getFullYear();
var month = currentdate.getMonth();
var day = currentdate.getDate();
var hour = countDownTo;
var minute = 0;
var second = 0;
cdown.add(new Date(year, month, day, hour, minute, second), "countbox1");
};
</script>
<span style="font-size:30px;"><div id="countbox1"></div></span>
<?php } ?>