JavaScript实现天时分秒倒计时功能详解

<div id="times_wrap" class="time_num">
 距离结束时间：
 <div class="time_w">
  <b id="times_d" class="time"> </b>天
  <b id="times_h" class="time"> </b>时
  <b id="times_m" class="time"> </b>分
  <b id="times_s" class="time"> </b>秒
 </div>
</div>

<script type="text/javascript">
setTimeout("show_time()",1000);
var time_wrap = document.getElementByIdx_x("times_wrap");
var time_d = document.getElementByIdx_x("times_d");
var time_h = document.getElementByIdx_x("times_h");
var time_m = document.getElementByIdx_x("times_m");
var time_s = document.getElementByIdx_x("times_s");

var time_end = new Date("2012/10/29 08:00:00"); // 设定结束时间
time_end = time_end.getTime();

function show_time(){
 var time_now = new Date(); // 获取当前时间
  time_now = time_now.getTime();
 var time_distance = time_end - time_now; // 结束时间减去当前时间
 var int_day, int_hour, int_minute, int_second;
 if(time_distance >= 0){
  // 天时分秒换算
  int_day = Math.floor(time_distance/86400000)
  time_distance -= int_day * 86400000;
  int_hour = Math.floor(time_distance/3600000)
  time_distance -= int_hour * 3600000;
  int_minute = Math.floor(time_distance/60000)
  time_distance -= int_minute * 60000;
  int_second = Math.floor(time_distance/1000)
 
  // 时分秒为单数时、前面加零站位
  if(int_hour < 10)
  int_hour = "0" + int_hour;
  if(int_minute < 10)
  int_minute = "0" + int_minute;
  if(int_second < 10)
  int_second = "0" + int_second;
  
  // 显示时间
  time_d.innerHTML = int_day;
  time_h.innerHTML = int_hour;
  time_m.innerHTML = int_minute;
  time_s.innerHTML = int_second;
  
  setTimeout("show_time()",1000);
 }else{
  time_d.innerHTML = time_d.innerHTML;
  time_h.innerHTML = time_h.innerHTML;
  time_m.innerHTML = time_m.innerHTML;
  time_s.innerHTML = time_s.innerHTML;
 
  // clearTimeout(timerID)
 }
};
</script>