jsp中想实现自动注销功能，使用$(function(){}提示无法定义$
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.util.*,dao.*,entity.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>用户信息</title>
</head>
<%
UserInfo user = (UserInfo)session.getAttribute("user");
if(null == user)
{
response.sendRedirect("login");
return;
} %>
<%
UserInfoDao dao=new UserInfoDao();
ArrayList<UserInfo> list=dao.findAll();
%>
<script type="text/javascript">
$(function(){//五分钟无操作，返回系统首页,timeToreturn.js
function timeToReturn(){
window.location.href = "http://localhost:8080/zhongCourt/";
}
var nowtime = Date.parse(new Date());
var timeend = Date.parse(new Date());
$("body").click(function(){
nowtime = Date.parse(new Date());
console.log("nowtime" + nowtime);
});
function check(){
timeend = Date.parse(new Date());
console.log("check");
if((timeend - nowtime) > 300000){
timeToReturn();
}
setTimeout(check,10000);
}
setTimeout(check,10000);
})
function myAction(pid){
document.forms[1].id.value=pid;
document.forms[1].submit();
}
</script>
<body>
欢迎您！<%=user.getUsercode() %>
<form action="loginout" method="post">
<input type="submit" name="注销" value="注销" onclick="mySubmit()">
</form>
<h1 align="center"><br></h1><h1 align="center"> 用户信息</h1>
<form action="webapp/doRemove.jsp" method="post">
<!-- 用于存放选择的id，然后会随表单提交给服务器处理页面 -->
<input type="hidden" name="id">
<table align="center" border="1" width="80%">
<tr>
<td colspan="6" align="right">
<a href="webapp/add.jsp">添加新信息</a>
</td>
</tr>
<tr>
<th>编号</th>
<th>姓名</th>
<th>性别</th>
<th>年龄</th>
<th>地址</th>
<th>操作</th>
</tr>
<%for(int i=0;i<list.size();i++){
UserInfo obj=list.get(i);%>
<!--Html代码-->
<tr>
<td><%=obj.getId()%></td>
<td><%=obj.getStu_name()%></td>
<td><%=obj.getGender()%></td>
<td><%=obj.getAge()%></td>
<td><%=obj.getAdress()%></td>
<td>
<%-- <a href="doRemove.jsp?id=<%=obj.getId()%>">删除</a> --%>
<a href="webapp/update.jsp?id=<%=obj.getId()%>">修改</a>
<input type="button" value="删除" onclick="myAction('<%=obj.getId()%>')"/>
</td>
</tr>
<%}%>
</table>
</form>
</body>
</html>求大佬帮助
<head> <script type="text/javascript" src="jquery.js"></script> </script> </head>
没有引入jquery文件
给力，可以了