JS倒计时

<span id="show">Loading...</span>
<script type="text/javascript">
function count_down(o){
var www_qsyz_net=/^[\d]{4}-[\d]{1,2}-[\d]{1,2}( [\d]{1,2}:[\d]{1,2}(:[\d]{1,2})?)?$/ig,str='',conn,s;
if(!o.match(www_qsyz_net)){
alert('参数格式为2012-01-01[ 01:01[:01]].\r其中[]内的内容可省略');
return false;
}
var sec=(new Date(o.replace(/-/ig,'/')).getTime() - new Date().getTime())/1000;
if(sec > 0){
conn='还有';
}else{
conn='已过去';
sec*=-1;
}
s={'天':sec/24/3600,'小时':sec/3600%24,'分':sec/60%60,'秒':sec%60};
for(i in s){
if(Math.floor(s[i])>0 ) str += Math.floor(s[i]) + i;
}
if(Math.floor(sec)==0){ str='0秒'; }
document.getElementById('show').innerHTML = '距离<u>' + o + '</u>' + conn +'<u>' + str + '</u>';
setTimeout(function(){count_down(o)},1000);
}
count_down('2012-10-1 22:55:40');
</script>