confirm--显示一个带有指定消息和 OK 及取消按钮的对话框

用户点击ok返回true，点击取消返回false

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
  <script type="text/javascript">
    function confirmDemo(){
      var boo = window.confirm("你带刺吗？");
      if(boo){
        alert("111");
      }else{
        alert("222");
      }
    }
  </script>
  <button οnclick="confirmDemo();">confirm</button>
</body>
</html>