aca dejo el script del reloj :   
Código Javascript
:
Ver original- <script type="text/javascript"> 
- function cdtd() { 
- var xmas = new Date("<?php echo $row_detalleofertas['fecha_de_cierre']; ?>"); 
- var now = new Date(); 
- var timeDiff = xmas.getTime() - now.getTime(); 
- if (timeDiff <= 0) { 
-         clearTimeout(timer); 
- document.write("Oferta Terminada!"); 
- // Run any code needed for countdown completion here 
-     } 
- var seconds = Math.floor(timeDiff / 1000); 
- var minutes = Math.floor(seconds / 60); 
- var hours = Math.floor(minutes / 60); 
- hours %= 24; 
-     minutes %= 60; 
-     seconds %= 60; 
- document.getElementById("hoursBox").innerHTML = hours; 
- document.getElementById("minsBox").innerHTML = minutes; 
- document.getElementById("secsBox").innerHTML = seconds; 
- var timer = setTimeout('cdtd()',1000); 
- } 
- </script>