Как сделать счетчик ?

[xfgiven_nextdate]Следующая дата оплаты: [xfvalue_nextdate]  (<span id="newyear"></span>)

<script type="text/javascript">// <![CDATA[
function newYearIn()
{
    var now = new Date();
    var newYear = new Date("[xfvalue_nextdate]");
    var totalRemains = (newYear.getTime()-now.getTime());
    if (totalRemains>1)
    {
        var RemainsSec=(parseInt(totalRemains/1000));
        var RemainsFullDays=(parseInt(RemainsSec/(24*60*60)));
        var secInLastDay=RemainsSec-RemainsFullDays*24*3600;
        var RemainsFullHours=(parseInt(secInLastDay/3600));
        if (RemainsFullHours<10){RemainsFullHours="0"+RemainsFullHours};
        var secInLastHour=secInLastDay-RemainsFullHours*3600;
        var RemainsMinutes=(parseInt(secInLastHour/60));
        if (RemainsMinutes<10){RemainsMinutes="0"+RemainsMinutes};
        var lastSec=secInLastHour-RemainsMinutes*60;
        if (lastSec<10){lastSec="0"+lastSec};
        var mcend = Date.parse("[xfvalue_nextdate]");
        var mcnow = now.getTime();
        var mc = ((mcend-mcnow)/10).toFixed(0).substr(8);
        document.getElementById('newyear').innerHTML = "осталось "+RemainsFullDays+" дней";
        setTimeout("newYearIn()",10);
    } 
    else {document.getElementById("newyear").innerHTML = "Продлите подписку!";}
}
window.onload = function () { newYearIn() }
// ]]></script>[xfvalue_nextdate]