为什么if里面设置disabled=""能实现，而设置disabled="false",反而实现不了？？？？
<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<script type="text/javascript">
window.onload=function(){
var send=document.getElementById('send'),
times=60,
timer=null;
send.onclick=function(){
// 计时开始
timer=setInterval(function(){
times--;
if(times<=0){
clearInterval(timer);
send.value="发送验证码";
send.disabled="";
times=60;
}else{
send.value=times+"秒后重试";
send.disabled="true";
}
},1000);
}
}
</script>
</head>
<body>
<input type="button" id="send" value="发送验证码">
</body>
</html>
