点击按钮怎么没反应

package com.imooc.servlet;
 
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import com.alibaba.fastjson.JSON;
 
/**
 * Servlet implementation class songservlet
 */
@WebServlet("/song")
public class songservlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
        
    /**
     * @see HttpServlet#HttpServlet()
     */
    public songservlet() {
        super();
        // TODO Auto-generated constructor stub
    }
 
    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String type = request.getParameter("t");
        List<String> list = new ArrayList<>();
        if(type.equals("popular")) {
            list.add("稻香");
            list.add("晴天");
            list.add("告白气球");
        }else if(type.equals("classic")) {
            list.add("千千阙歌");
            list.add("傻女");
            list.add("七友");
        }else if(type.equals("rock")) {
            list.add("一块红布");
            list.add("家行政");
            list.add("新长征路上的摇滚");
        }
        String json = JSON.toJSONString(list);
        System.out.println(json);
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().println(json);
      
    }
     
 
    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }
 
}

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-3.4.0.js"></script>
<script type="text/javascript">
 $(function()){
     $(".popular").click(function(){
            $.ajax({
                "url":"/FirstServlet/song",
                "type":"get",
                "data":"t=popular",
                "dataType":"json",
                "success":function(json) {
                    console.log(json);
                     for(var i =0;i<json.length;i++){
                         $("#song").append("<h1>"+json[i]+"<h1>");
                     }
                }
            })
        })
 }
     
</script>
</head>
<body>
  
    <input type="button" value="流行歌曲" id = "popular" class="popular">
    <input type="button" value="经典歌曲" id = "classic" class="classic">
    <input type="button" value="摇滚歌曲" id= "rock" class="rock">
    <div id="song"></div>
  
</body>
</html>