web页面显示当前系统时间并定时刷新

 function showCurrentDate(){
     var today,hour,second,minute,year,month,date;
     var strDate ;
     today=new Date();
     var n_day = today.getDay();
     switch (n_day)
     {
         case 0:{
           strDate = "星期日"
         }break;
         case 1:{
           strDate = "星期一"
         }break;
         case 2:{
           strDate ="星期二"
         }break;
         case 3:{
           strDate = "星期三"
         }break;
         case 4:{
           strDate = "星期四"
         }break;
         case 5:{
           strDate = "星期五"
         }break;
         case 6:{
           strDate = "星期六"
         }break;
         case 7:{
           strDate = "星期日"
         }break;
     }
     year = today.getYear()+1900;
     month = today.getMonth()+1;
     if(month<10){
         month="0"+month;
     }
     date = today.getDate();
     if(date<10){
         date="0"+date;
     }
     hour = today.getHours();
     if(hour<10){
         hour="0"+hour;
     }
     minute =today.getMinutes();
     if(minute<10){
         minute="0"+minute;
     }
     second = today.getSeconds();
     if(second<10){
         second="0"+second;
     }
     document.getElementById('currentDate').innerHTML = year + ":" + month + ":" + date + " " + strDate +" " + hour + ":" + minute + ":" + second; //显示时间
     window.setTimeout('showCurrentDate()',1000);
 }