【JS】显示网站运行时间-精确到秒

先亮出JS代码。可以直接放在引用的.js文件里：

function siteTime() {
    window.setTimeout("siteTime()", 1000);
    var seconds = 1000;
    var minutes = seconds * 60;
    var hours = minutes * 60;
    var days = hours * 24;
    var years = days * 365;
    var today = new Date();
    var todayYear = today.getFullYear();
    var todayMonth = today.getMonth() + 1;
    var todayDate = today.getDate();
    var todayHour = today.getHours();
    var todayMinute = today.getMinutes();
    var todaySecond = today.getSeconds();
    var t1 = Date.UTC(2022, 6, 1, 0, 0, 0);
    var t2 = Date.UTC(todayYear, todayMonth, todayDate, todayHour, todayMinute, todaySecond);
    var diff = t2 - t1;
    var diffYears = Math.floor(diff / years);
    var diffDays = Math.floor((diff / days) - diffYears * 365);
    var diffHours = Math.floor((diff - (diffYears * 365 + diffDays) * days) / hours);
    var diffMinutes = Math.floor((diff - (diffYears * 365 + diffDays) * days - diffHours * hours) / minutes);
    var diffSeconds = Math.floor((diff - (diffYears * 365 + diffDays) * days - diffHours * hours - diffMinutes * minutes) / seconds);
    document.getElementById("sitetime").innerHTML = diffYears + " 年 " + diffDays + " 天 " + diffHours + " 小时 " + diffMinutes + " 分钟 " + diffSeconds + " 秒";
}
siteTime();

直接在html中使用需要在代码前后添加<script>和</script>
然后在需要显示的地方写上下方代码即可：

<span id="sitetime"></span>

如果需要更改显示文本可以在sitetime函数的最后一行的innerHTML=后面修改

更新

最近有人在评论区提出了这段的代码中的许多问题，再此推荐一种更好的实现方法：

function siteTime(){
    window.setTimeout("siteTime()", 1000);
    const Jan=0,Feb=1,Mar=2,Apr=3,May=4,Jun=5,Jul=6,Aug=7,Sept=8,Oct=9,Nov=10,Dec=11, today = new Date();
	var UseYear = 1; 
    var t = Date.UTC(2024,Jun,23,00,00,00,000); //GMT Jun 1,2024 00:00:00.000
    var diff = today.getTime()-t-today.getTimezoneOffset()*60000;
    diff = Math.floor(diff/1000);
    var diffSeconds = diff%60; diff = Math.floor(diff/60);
    var diffMinutes = diff%60; diff = Math.floor(diff/60);
    var diffHours = diff%24; diff = Math.floor(diff/24);
	var diffDays = 0, diffYears = 0;
    if(UseYear){diffDays = diff%365; diffYears = Math.floor(diff/365);}
	else diffDays = diff;
	var f = 0, displayString = "";
	if(diffYears || f) displayString += diffYears+" 年 ", f=1;
	if(diffDays || f) displayString += diffDays+" 天 ", f=1;
	if(diffHours || f) displayString += diffHours+" 小时 ", f=1;
	if(diffMinutes || f) displayString += diffMinutes+" 分钟 ", f=1;
	displayString += diffSeconds+" 秒";
    document.querySelectorAll(".sitetime").forEach(function(currentValue){
        currentValue.innerHTML = displayString;
    });
}
siteTime();

来自：https://blog.air-kevin.rf.gd/2024/JS-SiteTime/

备用：https://web.archive.org/web/20240706031331/https://blog.air-kevin.rf.gd/2024/JS-SiteTime/?i=1