Cuenta regresiva con hora del servidor

[sebaocano]

Hola, mi problema es el siguiete: tengo una web donde hay cuenta regresiva de productos. El problema es que el tiempo restante depende del la hora del cliente ya que se hace en javascript.

La solucion seria poner el javascript con la hora del servidor por medio de php o de alguna otra forma. aca dejo el script usado:

intente cambiar la parte donde obtiene la hora actual, pero sin exito.
Especificamente esta linea: currentDate = Math.floor($.now() / 1000);


<script>
(function($) {
$.fn.countdown = function(options, callback) {

//custom 'this' selector
thisEl = $(this);

//array of custom settings
var settings = {
'date': null,
'date2': null,
'format': null
};

//append the settings array to options
if(options) {
$.extend(settings, options);
}

//main countdown function
function countdown_proc() {

eventDate = Date.parse(settings['date']) / 1000;

currentDate = Math.floor($.now() / 1000);


if(eventDate <= currentDate) {
callback.call(this);
clearInterval(interval);
}

seconds = eventDate - currentDate;

days = Math.floor(seconds / (60 * 60 * 24)); //calculate the number of days
seconds -= days * 60 * 60 * 24; //update the seconds variable with no. of days removed

hours = Math.floor(seconds / (60 * 60));
seconds -= hours * 60 * 60; //update the seconds variable with no. of hours removed

minutes = Math.floor(seconds / 60);
seconds -= minutes * 60; //update the seconds variable with no. of minutes removed

//conditional Ss
if (days == 1) { thisEl.find(".timeRefDays").text("day"); } else { thisEl.find(".timeRefDays").text("days"); }
if (hours == 1) { thisEl.find(".timeRefHours").text("hour"); } else { thisEl.find(".timeRefHours").text("hours"); }
if (minutes == 1) { thisEl.find(".timeRefMinutes").text("minute"); } else { thisEl.find(".timeRefMinutes").text("minutes"); }
if (seconds == 1) { thisEl.find(".timeRefSeconds").text("second"); } else { thisEl.find(".timeRefSeconds").text("seconds"); }

//logic for the two_digits ON setting
if(settings['format'] == "on") {
days = (String(days).length >= 2) ? days : "0" + days;
hours = (String(hours).length >= 2) ? hours : "0" + hours;
minutes = (String(minutes).length >= 2) ? minutes : "0" + minutes;
seconds = (String(seconds).length >= 2) ? seconds : "0" + seconds;
}

//update the countdown's html values.
if(!isNaN(eventDate)) {
thisEl.find(".days").text(days);
thisEl.find(".hours").text(hours);
thisEl.find(".minutes").text(minutes);
thisEl.find(".seconds").text(seconds);
} else {
alert("Invalid date. Here's an example: 12 Tuesday 2012 17:30:00");
clearInterval(interval);
}
}

//run the function
countdown_proc();

//loop the function
interval = setInterval(countdown_proc, 1000);

}
}) (jQuery);
</script>
<script>


$("#countdown").countdown({
//date: "17 august 2013 12:00:00",

date: "<?php echo date("d F Y",strtotime($fecha_finaliza)); ?> <?php echo $reg["hora_finaliza"] ?> ",
format: "on"
},

function() {
// callback function

});




</script>

saludos y gracias por tomarse su tiempo!