点击没反应，不知道哪里出错了

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%String basePath=request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath()+"/"; %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<script type="text/javascript" src="resources/js/jquery-1.4.2.js"></script>
<body>
<%-- <form action="<%=basePath%>LoginServlet" method="post"> --%>
<span id="tip"></span>
<table>
<tr><td>用户名：<input type="text" name="username"></td></tr>
<tr><td>密码：<input type="password" name="password"></td></tr>
<tr><td><input type="button" value="登录" id="login"></td></tr>
</table>
<!-- </form> -->
</body>
<script type="text/javascript">
$("#login").click(function(){
		//单击登录按钮的时候触发ajax事件
		$.ajax({
			url:"<%=basePath%>/LoginServlet",
			type:"post",
			data:{
				username:$("input[name=username]").val(),
				password:$("input[name=password]").val()
			},
			dataType:"json",
			success:function(result){
				var flag = result.flag;
				if(flag==true){
					//如果登录成功则跳转到成功页面
					window.location.href="<%=basePath%>success.jsp";
				}else{
					//跳回到Index.jsp登录页面，同时在登录页面给用户一个友好的提示
					$(".tip").text("您输入的用户名或者密码不正确");
				}
			}
			
		});
	});
</script>
</html>

package com.imooc.ajax;

import java.io.IOException;

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 org.json.JSONObject;

/**
 * Servlet implementation class LoginServlet
 */
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		JSONObject jsonobject=null;
		String name=request.getParameter("username");
		String password=request.getParameter("password");
		if("123456".equals(name)&&"123".equals(password)) {
			System.out.println(name);
			System.out.println(password);
			jsonobject=new JSONObject("{flag:true}");
			
		}else {
			jsonobject=new JSONObject("{flag:false}");
		}
		response.getOutputStream().write(jsonobject.toString().getBytes("utf-8"));
	}

	/**
	 * @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);
	}

}

慕粉2034367226 2018-12-10

源自：Ajax入门 2-1 使用Ajax实现登录的局部刷新