TargetDate = "05/13/2011 1:00 PM";//change this to the date you want
BackColor = "#800000";
ForeColor = "#FFFF00";
CountActive = true;
DisplayFormat = "%%D%% Days, %%H%% Hours<br>%%M%% Minutes, %%S%% Seconds";

<!--
function calcage(secs, num1, num2) {
s = ((Math.floor(secs/num1))%num2).toString();
if (s.length < 2)
s = "0" + s;
return "<b>" + s + "</b>";
}

function CountBack(secs) {
DisplayStr = DisplayFormat.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-1) + ")", 990);
}

function putspan(backcolor, forecolor) {
document.write("<span id='cntdwn' style='background-color:" + backcolor +
"; color:" + forecolor + "'></span>");
}

if (typeof(BackColor)=="undefined")
BackColor = "white";
if (typeof(ForeColor)=="undefined")
ForeColor= "black";
if (typeof(TargetDate)=="undefined")
TargetDate = "12/31/2020 5:00 AM";
if (typeof(DisplayFormat)=="undefined")
DisplayFormat = "%%D%% Days, %%H%% Hours, %%M%% Minutes, %%S%% Seconds.";
if (typeof(CountActive)=="undefined")
CountActive = true;
putspan(BackColor, ForeColor);
var dthen = new Date(TargetDate);
var dnow = new Date();
ddiff = new Date(dthen-dnow);
gsecs = Math.floor(ddiff.valueOf()/1000);
CountBack(gsecs);
//-->