<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<input type="button" value="alert" id="btn1">
<input type="button" value="prompt" id="btn2">
<input type="button" value="confirm" id="btn3">
<script>
var btn1 = document.getElementById('btn1');
var btn2 = document.getElementById('btn2');
var btn3 = document.getElementById('btn3');
btn1.onclick = function () {
alert('hello world');
}
btn2.onclick = function () {
var userName = prompt('请输入姓名', '张三');
console.log(userName);
}
btn3.onclick = function () {
var isSure = confirm('是否要删除数据？');
console.log(isSure);
}
</script>
</body>
</html>