代码：

<span id="momk"></span><span id="momk" style="color: #ff0000;"></span>
<script type="text/javascript">
function NewDate(str) {
str = str.split('-');
var date = new Date();
date.setUTCFullYear(str[0], str[1] - 1, str[2]);
date.setUTCHours(0, 0, 0, 0);
return date;
}
function momxc() {
var birthDay =NewDate("2020-11-11");
var today=new Date();
var timeold=today.getTime()-birthDay.getTime();
var sectimeold=timeold/1000
var secondsold=Math.floor(sectimeold);
var msPerDay=24*60*60*1000; var e_daysold=timeold/msPerDay;
var daysold=Math.floor(e_daysold);
var e_hrsold=(daysold-e_daysold)*-24;
var hrsold=Math.floor(e_hrsold);
var e_minsold=(hrsold-e_hrsold)*-60;
var minsold=Math.floor((hrsold-e_hrsold)*-60); var seconds=Math.floor((minsold-e_minsold)*-60).toString();
document.getElementById("momk").innerHTML = "本站已安全运行"+daysold+"天"+hrsold+"小时"+minsold+"分"+seconds+"秒";
setTimeout(momxc, 1000);
}momxc();
</script>  <style>
#momk{animation:change 10s infinite;font-weight:800; }
@keyframes change{0%{color:#5cb85c;}25%{color:#556bd8;}50%{color:#e40707;}75%{color:#66e616;}100% {color:#67bd31;}}
</style>

或
本站用的代码

<span id="runtime_span"></span>
<script type="text/javascript">function show_runtime(){window.setTimeout("show_runtime()",1000);X=new 

Date("10/01/2020 10:08:08");

Y=new Date();T=(Y.getTime()-X.getTime());M=24*60*60*1000;
a=T/M;A=Math.floor(a);b=(a-A)*24;B=Math.floor(b);c=(b-B)*60;C=Math.floor((b-B)*60);D=Math.floor((c-C)*60);
runtime_span.innerHTML="本站勉强运行: "+A+"天"+B+"小时"+C+"分"+D+"秒"}show_runtime();</script>
</a>