HTML获取当前页面的系统时间和星期几

获取当前时间并显示在页面上，顶部span的id为clock，底部span的id为footyear





<span id="clock"><span> <!--顶部span的id为clock-->

<div class="footer_copyright">
Copyright © 2015 - <span id="footyear"></span> Topinland. All Rights Reserved.<em>青岛天品网络科技有限公司 版权所有</em> <!--底部span的id为footyear-->
</div>

<script type="text/javascript">
function clock(){
var time=new Date();
var week;
switch (time.getDay()){ <!--time.getDay()获取后显示1~7阿拉伯数字-->
case 1: week="星期一"; break;
case 2: week="星期二"; break;
case 3: week="星期三"; break;
case 4: week="星期四"; break;
case 5: week="星期五"; break;
case 6: week="星期六"; break;
default: week="星期天";
}
var year=time.getFullYear();
var month=time.getMonth();
var date=time.getDate();
document.getElementById("clock").innerHTML = "今天是："+year+"年"+(month+1)+"月"+date+"日  "+week;
document.getElementById("footyear").innerHTML = year;
}
setInterval(clock,1000); <!--每隔1秒显示一次-->
</script>