Ajax 模拟动态列表

three.html

Java代码

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>index.html</title>
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=GBK">
<script type="text/javascript">
var xmlhttp;
function loadXMLDoc(valueFromSelect1){
var url = "three.jsp?valueFromSelect=" + valueFromSelect1 + "&" + Math.random();
alert(url);
xmlhttp=null;
if (window.XMLHttpRequest){
xmlhttp=new XMLHttpRequest();
}
else if (window.ActiveXObject){
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
if (xmlhttp!=null){
xmlhttp.onreadystatechange=updatePage;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}
else{
alert("Your browser does not support XMLHTTP.");
}
}
function state_Change(){
if (xmlhttp.readyState==4){
if (xmlhttp.status==200){
updatePage();
}
else{
alert("Problem retrieving XML data");
}
}
}
function updatePage(){
// 清空select2
while(select2.options[0] != null){
select2.options[0] = null;
}
// 设置select2
var xmlDoc = xmlhttp.responseXML;
alert(xmlDoc);
var labelValueBeanElements = xmlDoc.getElementsByTagName("labelValueBean");
for (var i = 0; i < labelValueBeanElements.length; i++){
var entityValue = xmlDoc.getElementsByTagName("value")[i].childNodes[0].nodeValue;
var entityLabel = xmlDoc.getElementsByTagName("label")[i].childNodes[0].nodeValue;
select2.options[i] = new Option(entityLabel,entityValue,false,false);
}
}
</script>
</head>
<body>
select1:
<select id="select1" onchange="loadXMLDoc(this.value)">
<option value="1">1</option>
<option value="2">2</option>
</select>
<br/>
select2:
<select id="select2">
</select>
<input type="button" value="显示select2的值" onclick="alert(select2.value)">
</body>
</html>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>index.html</title>
        <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
        <meta http-equiv="description" content="this is my page">
        <meta http-equiv="content-type" content="text/html; charset=GBK">
        <script type="text/javascript">
        var xmlhttp;
        function loadXMLDoc(valueFromSelect1){
            var url = "three.jsp?valueFromSelect=" + valueFromSelect1 + "&" + Math.random();
            alert(url);
            xmlhttp=null;
            if (window.XMLHttpRequest){
              xmlhttp=new XMLHttpRequest();
            }
            else if (window.ActiveXObject){
              xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
            if (xmlhttp!=null){
              xmlhttp.onreadystatechange=updatePage;
              xmlhttp.open("GET",url,true);
              xmlhttp.send(null);
            }
            else{
              alert("Your browser does not support XMLHTTP.");
            }
        }
        
        function state_Change(){
            if (xmlhttp.readyState==4){
                if (xmlhttp.status==200){
                    updatePage();
                }
                else{
                    alert("Problem retrieving XML data");
                }
            }
        }
        
        function updatePage(){            
            // 清空select2
            while(select2.options[0] != null){
                select2.options[0] = null;
            }
            
            // 设置select2
            var xmlDoc = xmlhttp.responseXML;
            alert(xmlDoc);
            var labelValueBeanElements = xmlDoc.getElementsByTagName("labelValueBean");
          
            for (var i = 0; i < labelValueBeanElements.length; i++){
                var entityValue = xmlDoc.getElementsByTagName("value")[i].childNodes[0].nodeValue;
                var entityLabel = xmlDoc.getElementsByTagName("label")[i].childNodes[0].nodeValue;
                select2.options[i] = new Option(entityLabel,entityValue,false,false);
            }
        }
        </script>
    </head>

    <body>
        select1:
        <select id="select1" onchange="loadXMLDoc(this.value)">
            <option value="1">1</option>
            <option value="2">2</option>
        </select>
        <br/>
        select2:
        <select id="select2">
        </select>
        <input type="button" value="显示select2的值" onclick="alert(select2.value)">
    </body>
</html>

three.jsp

Java代码

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%!
private String fromDB (String valueFromSelect) {
StringBuffer sb = new StringBuffer();
if (valueFromSelect.equals("1")) {
sb.append(" <labelValueBean>\n");
sb.append(" <value>haha</value>\n");
sb.append(" <label>哈哈</label>\n");
sb.append(" </labelValueBean>\n");
sb.append(" <labelValueBean>\n");
sb.append(" <value>hehe</value>\n");
sb.append(" <label>呵呵</label>\n");
sb.append(" </labelValueBean>\n");
} else if (valueFromSelect.equals("2")) {
sb.append(" <labelValueBean>\n");
sb.append(" <value>heihei</value>\n");
sb.append(" <label>嘿嘿</label>\n");
sb.append(" </labelValueBean>\n");
sb.append(" <labelValueBean>\n");
sb.append(" <value>gaga</value>\n");
sb.append(" <label>嘎嘎</label>\n");
sb.append(" </labelValueBean>\n");
sb.append(" <labelValueBean>\n");
sb.append(" <value>woyun</value>\n");
sb.append(" <label>我晕</label>\n");
sb.append(" </labelValueBean>\n");
sb.append(" <labelValueBean>\n");
sb.append(" <value>123</value>\n");
sb.append(" <label>456</label>\n");
sb.append(" </labelValueBean>\n");
}
return sb.toString();
}
%>
<%
String valueFromSelect = request.getParameter("valueFromSelect");
StringBuffer sb = new StringBuffer();
sb.append("<?xml version=\"1.0\" encoding=\"gb2312\"?>\n");
sb.append("<resultFromDB>\n");
sb.append(fromDB(valueFromSelect));
sb.append("</resultFromDB>\n");
response.setHeader("content-type", "text/xml;charset=GBK");
System.out.println(sb);
out.println(sb.toString());
//out.flush();
out.close();
%>

Ajax 模拟动态列表

Ajax 模拟动态列表

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