Brug af javascripts setTimeout- og setInterval-metoder er selvfølgelig potentielt ikke tidsægte, ligesom de metoder enten skal tage udgangspunkt i klientens egen tidsformattering eller en angivet værdi, udsendt fra serveren, som måske ikke er helt præcis ...
-- men da clock-timeren er helt grundlæggende for computerens funktion, tror jeg ikke du kan nå at få væsentlige udsving, selv over mange døgn, hvis du netop selv medsender en start-tid og hele tiden korrellerer med forskellen mellem den og den lokale tid !-)
Uden korrellation, har jeg tidligere lavet denne:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"
http://www.w3.org/TR/html4/loose.dtd"><html>
<head>
<title>Multiple times</title>
<meta name="Generator" content="Stone's WebWriter 4">
<meta name="keywords" content="roenving">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css">
html,body{height:100%;margin:0px;border:0px;padding:0px;font-family:tahoma,verdana,arial,sans-serif;font-size:small;}
</style>
<script language="javascript" type="text/javascript">
var todayColor = "#000";
var tomorrowColor = "#00f";
var yesterdayColor = "#f00";
function showTime(){
var lt = new Date();
var l = document.getElementById('local');
l.innerHTML = lt.toLocaleTimeString();
l.style.color = todayColor;
var bt = new Date(lt.getUTCFullYear(),lt.getUTCMonth(),lt.getUTCDate(),lt.getUTCHours()+10,lt.getUTCMinutes(),lt.getUTCSeconds(),lt.getUTCMilliseconds());
var b = document.getElementById('beijing')
b.innerHTML = bt.toLocaleTimeString();
b.style.color = (bt.getDate()==lt.getDate())?todayColor:(bt.getDate()>lt.getDate())?tomorrowColor:yesterdayColor;
var ct = new Date(lt.getUTCFullYear(),lt.getUTCMonth(),lt.getUTCDate(),lt.getUTCHours()+1,lt.getUTCMinutes(),lt.getUTCSeconds(),lt.getUTCMilliseconds());
var c = document.getElementById('chagen')
c.innerHTML = ct.toLocaleTimeString();
c.style.color = (ct.getDate()==lt.getDate())?todayColor:(ct.getDate()>lt.getDate())?tomorrowColor:yesterdayColor;
var mt = new Date(lt.getUTCFullYear(),lt.getUTCMonth(),lt.getUTCDate(),lt.getUTCHours()+3,lt.getUTCMinutes(),lt.getUTCSeconds(),lt.getUTCMilliseconds());
var m = document.getElementById('moscow')
m.innerHTML = mt.toLocaleTimeString();
m.style.color = (mt.getDate()==lt.getDate())?todayColor:(mt.getDate()>lt.getDate())?tomorrowColor:yesterdayColor;
var nt = new Date(lt.getUTCFullYear(),lt.getUTCMonth(),lt.getUTCDate(),lt.getUTCHours()-4,lt.getUTCMinutes(),lt.getUTCSeconds(),lt.getUTCMilliseconds());
var n = document.getElementById('newyork')
n.innerHTML = nt.toLocaleTimeString();
n.style.color = (nt.getDate()==lt.getDate())?todayColor:(nt.getDate()>lt.getDate())?tomorrowColor:yesterdayColor;
}
</script>
</head>
<body onresize onload="showTime();setInterval('showTime()',1000)">
Time in different sites around the world (blue is tomorrows date, red yesterdays):<br>
Your time: <span id="local"></span><br>
Time in Beijing: <span id="beijing"></span> (standard time -- no daylight savings)<br>
Time in Moscow: <span id="moscow"></span> (standard time -- no daylight savings)<br>
Time in Copenhagen: <span id="chagen"></span> (standard time -- no daylight savings)<br>
Time in New York: <span id="newyork"></span> (standard time -- no daylight savings)
</body>
</html>
