为什么parent在控制台输出不了？
来源：3-8 实现二级联动菜单-2
慕先生8069638
2019-07-20 18:22:09
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-3.4.1.js"></script>
<script type="text/javascript">
$(function(){
$.ajax({
"url":"/jquery/part",
"type":"get",
"data":{"level":"1"},
"dataType":"json",
"success":function(json){
for(var i=0;i<json.length;i++){
var ch=json[i];
$("#lv1").append("<option value='ch.code'>"+ch.name+"</option>");
}
}
})
})
$(function(){
$("#lv1").on("change",function(){
var parent=$(this).val();
console.log(parent);
})
})
</script>
</head>
<body>
<select id="lv1" style="width:200px;height:30px">
<option selected="selected">请选择</option>
</select>
<select id="lv2" style="width:200px;height:30px"></select>
</body>
</html>
package com.imooc.jquery;
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 ChannelServlet
*/
@WebServlet("/part")
public class ChannelServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public ChannelServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String level=request.getParameter("level");
String parent=request.getParameter("parent");
List chlist=new ArrayList();
if(level.equals("1")) {
chlist.add(new Channel("ai","前沿/区块链/人工智能"));
chlist.add(new Channel("web","前端/小程序/js"));
}else if(level.equals("2")) {
if(parent.equals("ai")) {
chlist.add(new Channel("micro","微服务"));
chlist.add(new Channel("blockchain","区块链"));
chlist.add(new Channel("other","..."));
}else if(parent.equals("web")) {
chlist.add(new Channel("html","HTML"));
chlist.add(new Channel("css","CSS"));
chlist.add(new Channel("other","..."));
}
}
response.setContentType("text/html;charset=utf-8");
String json=JSON.toJSONString(chlist);
response.getWriter().println(json);
}
}
1回答
-
同学你好，选择具体的一级分类后，是可以显示，但是显示的ch.code，如：
在设置option标签时，设置value为ch.code，如：
所以这里获取的是ch.code。如果将这里value='ch.code'去掉，可以获取具体的分类信息。
如果我的回答解决了你的疑惑，请采纳。祝：学习愉快~
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