<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<input type="text"/>
<button id="btn">点击发送短信</button>
</body>
</html>
<script>
var btn = document.getElementById("btn");
var count = 5; //数据的
var timer = null ; //定时器的名字
btn.onclick = function(){
clearInterval(timer); //先清除原先的定时器
this.disabled = true ; //禁用当前的button this一般使用在函数里面，当前值得是button
var that = this //把btn对象给 that
timer = setInterval(sendTextMessage,1000);//开启定时器 定时器的 名字是timer
function sendTextMessage(){
alert(this);
alert(that);
count--;
if(count >= 0){
that.innerHTML = "还剩余"+count+"秒";
}else{
that.innerHTML = "重新发送短信";
that.disabled = false;
clearInterval(timer);//清除定时器
count = 5;
}
}
}
</script>
原文：http://www.cnblogs.com/aa-bb/p/6021656.html