请问怎么实现冒号跳动
代码如下
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>定时器</title>
<script type="text/javascript">
var attime;
function clock(){
var time=new Date();
attime=time.getHours()+":"+time.getMinutes()+":"+time.getSeconds();
document.getElementById("clock").value = attime;
}
setInterval(clock,1000)
</script>
</head>
<body>
<form>
<input type="text" id="clock" size="50" style="background:black;color:#0f0;font-size:50px;width:200px;text-align:center"/>
</form>
</body>
</html>
一般时钟都带冒号跳动的效果,但是实在不知道怎么实现。求大神给个方案或者思路~谢谢