ajax中getElementsByTagName是什么意思？

ajax中getElementsByTagName是什么意思？

tonnye888
tonnye
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发表于：2008-05-13 20:56:14 楼主

看了一个例子没有看懂有点问题请教
TESTA.JAVA
package tt;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class TestA extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

request.setCharacterEncoding("UTF-8");

String name=request.getParameter("name");

response.setContentType("text/xml; charset=UTF-8");
response.setHeader("Cache-Control","no-cache");

PrintWriter out=response.getWriter();

out.println(" <pront>");
if(name.equals("jack_booth")){
out.println(" <content>"+"被注册了!"+" </content>");

}else{
out.println(" <content>"+"没有被注册!"+" </content>");
}
out.println(" </pront>");
out.close();

}

}

INDEX.htm:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<script>

//设一个变量

var XMLHttpReq=false;
//创建一个XMLHttpRequest对象
function createXMLHttpRequest(){
if(window.XMLHttpRequest){ //Mozilla
XMLHttpReq=new XMLHttpRequest();
}
else if(window.ActiveXObject){
try{
XMLHttpReq=new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
try{
XMLHttpReq=new ActiveXObject("Microsoft.XMLHTTP");
}catch(e){}
}
}
}
//发送请求函数
function send(url){
createXMLHttpRequest();
XMLHttpReq.open("GET",url,true);
XMLHttpReq.onreadystatechange=proce; //指定响应的函数
XMLHttpReq.send(null); //发送请求
}
function proce(){
if(XMLHttpReq.readyState==4){ //对象状态
if(XMLHttpReq.status==200){//信息已成功返回，开始处理信息
var res=XMLHttpReq.responseXML.getElementsByTagName("content")[0].firstChild.data;
window.alert(res);
}else{
window.alert("所请求的页面有异常");
}
}
}
//身份验证
function check(){
var name=document.getElementById("name").value;

if(name==""){
alert("请输入姓名");
return false;
}
else{
send('login?name='+name);
}
}

</script>
</head>

<body>
<table>
<form action="login" method="post">
<tr> <td>姓名:  <input id="name" type="text" name="name"/> <p>
<input type="button" value="检测!" onClick="check()"/>
</td>
</tr>
</form>
</table>
</body>
</html>
我的问题是：
1.var res=XMLHttpReq.responseXML.getElementsByTagName("content")[0].firstChild.data;这句话中是什么意思？content在哪里呢？

问题点数：20 回复次数：6 修改删除举报引用回复

<SCRIPT> var aSpans = oDiv.getElementsByTagName("SPAN"); </SCRIPT> <DIV id="oDiv"> <SPAN>Immediate Child <DIV> <SPAN>Child of Child DIV</SPAN> </DIV> </SPAN> </DIV>

<html> <head> <script type="text/javascript"> function getElements() { var x=document.getElementsByTagName("input"); alert(x.length); } </script> </head> <body> <input name="myInput" type="text" size="20" /><br /> <input name="myInput" type="text" size="20" /><br /> <input name="myInput" type="text" size="20" /><br /> <br /> <input type="button" onclick="getElements()" value="How many input elements?" /> </body> </html>