JS 动态显示时间 精确到秒 显示第几周的代码

代码如下：

<script type="text/javascript">
/**
 * 动态显示时间 精确到秒
 * www.jb200.com
*/
function gettime()
{ 
   var t = new Date();
   var year = t.getFullYear();       //年
   var month = t.getMonth() + 1;     //月
   var day = t.getDate();            //日
   var hours = t.getHours();
   var minutes = t.getMinutes();
   var seconds = t.getSeconds();
   var week = t.getDay();
   var weekArr = new Array('周日','周一','周二','周三','周四','周五','周六');
   week = weekArr[week];
   var show_str ="";
   var show_str = year + "年";         
     if(month < 10)
        show_str += "0";        
        show_str += month + "月";
        if(day < 10)
          show_str += "0";
          show_str += day + "日 ";
   show_str +=(hours > 12) ? "下午 ": "上午 ";
   show_str += ((hours > 12) ? hours-12 : hours);
   show_str += ((minutes <10) ? ":0" : ":") + minutes;
   show_str += ((seconds <10) ? ":0" : ":") + seconds;
   show_str += '  '+week;
   $("#led_date").html(show_str);    //jquery 代码
   timerID = setTimeout(function(){gettime()},1000);
  }
 </script>