📄 menu.jsp
字号:
<%@ page language="java" import="java.util.*,java.sql.*" pageEncoding="UTF-8"%>
<%
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
%>
<html>
<head>
<META http-equiv=Content-Type content="text/html; charset=UTF-8">
<!--LINK href="images/css.css" type=text/css rel=stylesheet-->
</head>
<%
String driver = "com.mysql.jdbc.Driver";
String connectionURL = "jdbc:mysql:///test";
Connection conn = null;
Statement st = null;
ResultSet rs = null;
List cities = new ArrayList();
try{
Class.forName(driver);
} catch(java.lang.ClassNotFoundException e) {
e.printStackTrace();
}
try {
conn = DriverManager.getConnection(connectionURL,"root","root");
st=conn.createStatement();
rs=st.executeQuery("SELECT distinct dname FROM emp");
while (rs.next())
{
cities.add(rs.getString(1));
}
rs.close();
st.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
%>
<body>
<script language="javascript">
var XMLHttpReq;
var currentSort;
//创建XMLHttpRequest对象
function createXMLHttpRequest() {
if(window.XMLHttpRequest) { //Mozilla 浏览器
XMLHttpReq = new XMLHttpRequest();
}
else if (window.ActiveXObject) { // IE浏览器
try {
XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
}
//发送请求函数
function sendRequest(url) {
createXMLHttpRequest();
XMLHttpReq.open("GET", url, true);
XMLHttpReq.onreadystatechange = processResponse;//指定响应函数
XMLHttpReq.send(null); // 发送请求
}
// 处理返回信息函数
function processResponse() {
if (XMLHttpReq.readyState == 4) { // 判断对象状态
if (XMLHttpReq.status == 200) { // 信息已经成功返回，开始处理信息
updateMenu();
} else { //页面不正常
alert("您所请求的页面有异常。");
}
}
}
//更新菜单函数
function updateMenu() {
var res=XMLHttpReq.responseXML.getElementsByTagName("res")
/**下面是用innerHTML输出控件内容的一般用法**/
//var subMenu = "";
//for(var i = 0; i < res.length; i++) {
// subMenu = subMenu + " " + res[i].firstChild.data + "";
//}
//currentSort.innerHTML = subMenu;
var list = document.all.list;
list.options.length=0;
list.add(new Option("---请选择---",""));
for(var i=0;i<res.length;i++){
list.add(new Option(res[i].firstChild.data,res[i].firstChild.data));
}
}
// 创建级联菜单函数
function showSubMenu(obj) {
sendRequest("menujsp.jsp?sort=" + obj);
/**下面这一句的作用是：每次选择后回到第一个选项**/
//document.all.mli.options[0].selected=true;
}
</script>
<select onchange="showSubMenu(this.options[this.options.selectedIndex].value)" name="mli" style="width:150px">
<option value=''>---请选择---</option>
<%
for(int i=0;i<cities.size();i++)
{
out.println("<option value='"+cities.get(i)+"'>"+cities.get(i)+"</option>");
}
%>
</select>
<select name="list" onchange="if(this.selectedIndex)alert(this.options[this.options.selectedIndex].value)" style="width:100px">
<option name="">---请选择---</option>
</select>
</body>
</html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -