<script>    
function nowtime()
          {
                var date =new Date();
                //当前年份
                var year=date.getFullYear();
                //当前月份
                var month=date.getMonth()+1;
                //当前天数
                var day=date.getDate();
                //当前小时
                var hour=date.getHours();
                //当前分钟
                var minutes=date.getMinutes();
                //当前秒
                var seconds=date.getSeconds();
                //当前星期
                var weeks=date.getDay();
                var days=["天","一","二","三","四","五","六"];
                var showtime=document.getElementById("showtime");
                showtime.innerHTML=year+"年"+month+"月"+day+"日"+hour+"时"+minutes+"分"+seconds+"秒"+"星期"+days[weeks];
            }
    //每秒执行一次
    window.setInterval('nowtime()',1000);
 </script>