【ajax】初学可运行示例

一、准备

1、 tomcat解压文件目录下找到 webapps目录建立TestAjax文件夹

3、在RWQAjax文件夹内建立如下jsp文件

二、代码

ajaxTeset.jsp

<%@pagelanguage="java"contentType="text/html;charset=GBK"%>
<!DOCTYPEhtmlPUBLIC"-//W3C//DTDXHTML1.0Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<Metahttp-equiv="Content-Type"content="text/html;charset=utf-8"/>
<title>登录</title>
<scripttype="text/javascript">
varreq;
functionvalidate(){
varnameid=document.getElementById("userId");
varurl="validate.jsp?id="+escape(nameid.value);
if(window.XMLHttpRequest){
req=newXMLHttpRequest();
}elseif(window.ActiveXObject){
req=newActiveXObject("Microsoft.XMLHTTP");
}
req.open("GET",url,true);
req.onreadystatechange=callback;
req.send(null);
}
functioncallback(){
if(req.readyState==4){
if(req.status==200){
varmsg=req.responseXML.getElementsByTagName("msg")[0];
setMsg(msg.childNodes[0].nodeValue);
}
}
}
functionsetMsg(msg){
mdiv=document.getElementById("usermsg");
if(msg=="invalid"){
mdiv.innerHTML="不存在"
}else{
mdiv.innerHTML="Valid"
}
}
</script>
</head>
<body>
<formaction=""method="post">
<div
style="border-color:#0FF;width:300px;height:200px;margin:0auto;text-align:center;margin-top:50px;">
<div
style="border-color:#0FF;width:250px;height:50px;margin:0auto;text-align:center;margin-top:20px;">
<div>
<label>用户：</label><inputtype="text"name="user"id="userId"onblur="validate();"/>
</div>
<divid="usermsg">
</div>
<divstyle="margin-top:10px;margin-bottom:10px;">
密码：<inputtype="password"name="password"/>
</div>
<div>
<inputstyle="margin-right:30px;"type="submit"value="登陆"/>
</div>
</div>
<div></div>
</div>
</form>
</body>
</html>

<%@page language="java" contentType="text/html; charset=GBK"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<Meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>登录</title>

<script type="text/javascript">
 var req;
function validate(){
 var  nameid = document.getElementById("userId");
 var url="validate.jsp?id="+escape(nameid.value);
 if(window.XMLHttpRequest){
   req=new XMLHttpRequest();
}else if(window.ActiveXObject){
	req=new ActiveXObject("Microsoft.XMLHTTP");
}
req.open("GET",true);
req.onreadystatechange=callback;
req.send(null);
}

function callback(){
if(req.readyState==4){
  if(req.status==200){
  var msg = req.responseXML.getElementsByTagName("msg")[0];
  setMsg(msg.childNodes[0].nodeValue);
}
}
}
function setMsg(msg){
 mdiv = document.getElementById("usermsg");
 if(msg=="invalid"){
 mdiv.innerHTML="不存在"
 }else{
 mdiv.innerHTML="Valid"
}
}
</script>
</head>
<body>
	<form action="" method="post">
		<div
			style="border-color: #0FF; width: 300px; height: 200px; margin: 0 auto; text-align: center; margin-top: 50px;">
			<div
				style="border-color: #0FF; width: 250px; height: 50px; margin: 0 auto; text-align: center; margin-top: 20px;">
				<div>
					<label>用户：</label><input type="text" name="user" id="userId" onblur="validate();"/>
				</div>
				<div  id="usermsg">
				
				</div>
				<div style="margin-top: 10px; margin-bottom: 10px;">
					密码：<input type="password" name="password" />
				</div>
				<div>
					<input style="margin-right: 30px;" type="submit" value="登陆" />
				</div>
			</div>
			<div></div>
		</div>
	</form>
</body>
</html>

validate.jsp

【ajax】初学可运行示例

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