HTML代码：

<div id="show"></div>

Js代码：

window.onload = function showTime(){
    var now=new Date(); 
    var year=now.getFullYear(); 
    var month=now.getMonth(); 
    var date=now.getDate(); 
    var day=now.getDay(); 
    var hours=now.getHours();
    var minutes=now.getMinutes();
    var seconds=now.getSeconds();
    var week;
    month=month+1;
    var arr_week=new Array("星期日","星期一","星期二","星期三","星期四","星期五","星期六");
    week=arr_week[day]; 
    document.all.show.innerHTML=year+"年"+month+"月"+date+"日 "+week+" "+hours+":"+minutes+":"+seconds; 
    var timeID=setTimeout(showTime,1000);
}