Using jquery's ajax to implement a two-level interactive menu_javascript skills

<%@ page contentType="text/html; charset=gbk "%>
<%@ taglib prefix="s" uri="/struts-tags"%>


<% String basePath = request.getScheme() "://" request.getServerName() ":" request.getServerPort() request.getContextPath() "/";
out.println(basePath);
%>

< ;script type="text/javascript">
jQuery(function($){
//alert("ok");
});
function onchangeShow(oneId){
$.ajax({
url : "<%=basePath%>cateJson.whbs",
data : {parentId : oneId}, // Parameters
type : "post",
cache : false,
dataType : "json", //Return json data
error: function(){
alert('error');
},
success:onchangecallback
});
}
function onchangecallback(data){
document.all['twoId'].options.length = 0; //Clear the original options
var str=" ";
for(var i=0;istr ="" data[i]. title ""
}
$("#twoId").html(str);
}

Please select the department type


Please select the file type
< ;s:select list="rftwos" listKey="recordId" listValue="title" name="twoId" theme="simple" id="twoId" value="twoID">

/**
* des: Get the secondary linkage menu
* autho:exceljava
* date:Nov 20, 2009
* @return
* @throws IOException
*/
public String getJsonCategory() throws IOException{
rfjsons=archiveService.getCategoryByParentID(parentId);//Get data from the database here
net.sf.json.JSONArray jsonObj=net.sf.json.JSONArray.fromObject(rfjsons);//Assemble into json data
sendMessage(jsonObj.toString());//push json data to the view
return null;
}
/**
* des: encapsulates sending data in json format back to js
* autho:exceljava
* date:Nov 20, 2009
* @param content
* @throws IOException
*/
public void sendMessage(String content) throws IOException{
HttpServletResponse response = ServletActionContext.getResponse();
response.setCharacterEncoding("UTF-8");
response.getWriter().write(content);

}