aver es que tengo esto para crear un time de tiempo de cuanto lleva el foro activo
    
Código Javascript
:
Ver originalfunction calcage(secs, num1, num2) {
  s = ((Math.floor(secs/num1))%num2).toString();
  if (LeadingZero && s.length < 2)
    s = "0" + s;
  return  s;
}
 
function CountBack(secs) {
  if (secs < 0) {
    document.getElementById("cntdwn").innerHTML = FinishMessage;
    return;
  }
  DisplayStr = DisplayFormat.replace(/%%W%%/g, calcage(secs,86400000,7));
  DisplayStr = DisplayStr.replace(/%%D%%/g, calcage(secs,86400,100000));
  DisplayStr = DisplayStr.replace(/%%H%%/g, calcage(secs,3600,24));
  DisplayStr = DisplayStr.replace(/%%M%%/g, calcage(secs,60,60));
  DisplayStr = DisplayStr.replace(/%%S%%/g, calcage(secs,1,60));
 
  document.getElementById("cntdwn").innerHTML = DisplayStr;
  if (CountActive)
    setTimeout("CountBack(" + (secs+CountStepper) + ")", SetTimeOutPeriod);
}
 
function putspan(backcolor, forecolor) {
 document.write("<span id='cntdwn'></span>");
}
 
if (typeof(BackColor)=="undefined")
  BackColor = "white";
if (typeof(ForeColor)=="undefined")
  ForeColor= "#2A8827";
if (typeof(TargetDate)=="undefined")
  TargetDate = "12-31-2020 5:00 AM";
if (typeof(DisplayFormat)=="undefined")
  DisplayFormat = "%%W%%w %%D%%d %%H%%h %%M%%m %%S%%s.";
if (typeof(CountActive)=="undefined")
  CountActive = true;
if (typeof(FinishMessage)=="undefined")
  FinishMessage = "no data";
if (typeof(CountStepper)!="number")
  CountStepper = +1;
if (typeof(LeadingZero)=="undefined")
  LeadingZero = true;
 
 
CountStepper = Math.ceil(CountStepper);
if (CountStepper == 0)
  CountActive = false;
var SetTimeOutPeriod = (Math.abs(CountStepper)-1)*1000 + 1000;
putspan(BackColor, ForeColor);
var dthen = new Date(TargetDate);
var dnow = new Date();
if(CountStepper>0)
  ddiff = new Date(dnow-dthen);
else
  ddiff = new Date(dthen-dnow);
gsecs = Math.floor(ddiff.valueOf()/1000);
CountBack(gsecs);
  
codigo que muestra el tiempo    
Código PHP:
Ver original<html>
<head>
</head>
 
<body>
<?php
$date = new DateTime('2012-10-17 03:14:15');
$start = $date->format('Y/m/d h:i:s');
?> 
<br>
Fecha:<script type="text/javascript" language="JavaScript">
    TargetDate = "<?php echo $start; ?>";
    CountActive = true;
</script>
<script type="text/javascript"  language="JavaScript" src="js/time.js"></script>
</body>
</html>