解決不了Javascript計時器

Question

我在這個頁面上的計時器http://jian.comoj.com/countdown.php不倒計時。我按照這樣做的視頻教程，但不知何故有什麼錯，我不知道它是什麼。

<?php 
include "connect.php"; 
$query= "select * from product where product_id='1'"; 
$result= mysql_query($query); 
$record= mysql_fetch_object($result); 
$time= $record->end_time; 
date_default_timezone_set('Asia/Singapore'); 
$unix_time= strtotime($time); 

？>

<script type="text/javascript"> 

    function countdown(){ 

     <?php 
      $now= time(); 

      $sec= $unix_time-$now; 

      $min= $sec/60; 

      $hour= $min/60; 

      $sec %= 60; 

      $min %= 60; 
      ?> 

     var hour= <?php echo floor($hour); ?>; 
     var min= <?php echo $min; ?>; 
     var sec= <?php echo $sec; ?>; 
     document.getElementById("hour").innerHTML = hour; 
     document.getElementById("min").innerHTML = min; 
     document.getElementById("sec").innerHTML = sec; 
     setInterval('countdown()',1000); 
    } 

</script> 

<div id="hour"></div> 
<div id="min"></div> 
<div id="sec"></div> 

<script type="text/javascript">countdown();</script> 

Answer 1

function countdown(){ 

     var hour= 3; 
     var min= 39; 
     var sec= 58; 
     document.getElementById("hour").innerHTML = hour; 
     document.getElementById("min").innerHTML = min; 
     document.getElementById("sec").innerHTML = sec; 
     setTimeout('countdown()',1000); 
    } 

看一下函數它們固定即小時，分鐘和秒。