<body>
<div id="a"></div>
</body>
</html>
<script>
window.setInterval("asd()",500);
function asd(){
var zxc_b = new Date();
var year = zxc_b.getFullYear();//年
var month = zxc_b.getMonth()+1;//月
var dat = zxc_b.getDate(); //日
var hours = zxc_b.getHours(); //时
var min = zxc_b.getMinutes(); //分
var sec = zxc_b.getSeconds(); //秒
var zxc = year+'年'+month+'月'+dat+'日'+hours+'：'+min+'：'+sec;
document.getElementById("a");
a.innerHTML=zxc;
}
// window.setInterval("asd()",500);
</script>
