<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
a{
color:red;
}
.disable{
pointer-events:none;
color:#666;
}
</style>
</head>
<body>
<a href="javascript:;" id="btn">发送验证码</a>
<script>
var oBtn=document.getElementById("btn");
oBtn.onclick=function(){
oBtn.classList.add("disable");
setTimeout(function(){
oBtn.classList.remove('disable');
},3000)
};
</script>
</body>
</html>