一个实现了在按钮上显示倒计时，倒计时完毕自动将按钮设置为不可用的效果，具体代码如下：
<html>
<head>
<title>test count down button</title>
<script src="https://www.feishuai.vip/js/jquery.js" type="text/javascript"></script>
<script type="text/javascript">
$(function ( {
$('#btn'.click(function ( {
var count = 3;
var countdown = setInterval(CountDown, 1000;
function CountDown( {
$("#btn".attr("disabled", true;
$("#btn".val("Please wait " + count + " seconds!";
if (count == 0 {
$("#btn".val("Submit".removeAttr("disabled";
clearInterval(countdown;
}
count--;
}
}
};
</script>
</head>
<body>
<input type="button" id="btn" value="Submit" />
</body>
</html>