问题相关代码，请勿粘贴截图
上面的书上的内容.下面是我写的代码
第一个jsp页面:
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
#div {
width: 200px;
height: 200px;
position: absolute;
}
</style>
</head>
<body>
<form action="">
<input id="name" name="name"><br/>
<input type="password" id="pwd" name="pwd"><br/>
<input type="submit" onclick="check()" value="按钮">
<div id="div"></div>
</form>
</body>
<script>
var http_request = new XMLHttpRequest();
function createRequest(url) {
var http_request = false;
if (window.XMLHttpRequest) {
http_request = new XMLHttpRequest();
}else if (window.ActiveXObject){
try {
http_request = new ActiveXObject("Msxml2.XMLHTTP");
}catch (e) {
try {
http_request = new ActiveXObject("Microsoft.XMLHTTP");
}catch (e) {
}
}
if (http_request) {
alert("不能创建对象");
return false;
}
}
http_request.onreadystatechange = get_result; //调用返回结果处理函数
body.innerText = "调用返回结果处理函数\n";
http_request.open("GET", url, true); //创建与服务器的连接
body.innerText = "创建与服务器的连接\n";
http_request.send(null); //向服务器发送请求
body.innerText = "向服务器发送请求\n";
}
function get_result() {
if (http_request.status === 4) { //判断请求状态
if (http_request.status === 200) { //请求成功,开始处理返回结果
document.getElementById("div").innerHTML = http_request.responseText; //设置提示内容
document.getElementById("div").style.display = "block" //显示提示框
}else {
alert("访问错误");
}
}
}
function check() {
var username = document.getElementById("name").value;
if (username === "") {
alert("请输入用户名");
username.focus();
return;
}else {
createRequest("test.jsp?user=" + username);
body.innerText = "创建请求\n";
}
}
</script>
</html>
第二个jsp页面:
<%@page import="java.util.ArrayList"%>
<%@page import="java.util.List"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
List<String> list = new ArrayList<>();
list.add("zhangsan");
list.add("lisi");
list.add("wangwu");
String user = request.getParameter("name") + "";
int result = list.indexOf(user);
if (result != -1) {
out.print("该用户已被注册");
}else {
out.print("注册成功");
}
%>
</body>
</html>
运行结果及报错内容
运行结果没反应
