ajax学习
HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<TITLE> ajax passport </TITLE>
<style>
body{
font-size:14px;
}
</style>
<SCRIPT LANGUAGE="JavaScript">
<!--
function InitAjax(){
var http_request = false;
if (window.XMLHttpRequest){
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType){
http_request.overrideMimeType('text/xml');
}
}else if (window.ActiveXObject){
try{
http_request = new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e){
try{
http_request = new ActiveXObject("Microsoft.XMLHTTP");
}catch (e)
{}
}
}
if (!http_request){
alert('Giving up :( Cannot create an XMLHTTP instance');
return false;
}
return http_request;
}
function IDRequest(n)
{
//定义收到服务器的响应后需要执行的JavaScript函数
var proxy = "proxy.php?uid="
url=proxy+document.getElementById('username').value;//定义网址参数
xmlhttp_request=InitAjax();//调用创建XMLHttpRequest的函数
xmlhttp_request.open('GET', url, true);
xmlhttp_request.send(null);
xmlhttp_request.onreadystatechange = doContents;//调用doContents函数
}
function doContents()
{
if (xmlhttp_request.readyState == 4)
{
// 收到完整的服务器响应
if (xmlhttp_request.status == 200)
{
//HTTP服务器响应的值OK
var response = xmlhttp_request.responseXML.documentElement;
var result = response.getElementsByTagName('result')[0].firstChild.data;//返回result节点数据
if(result ==-2)
{
document.getElementById('message').innerHTML = "<span style='color:green'>用户名 "+document.getElementById('username').value+" 尚未注册</span>";
}
else if(result ==-1)
{
document.getElementById('message').innerHTML = "<span style='color:red'>对不起,用户名"+document.getElementById('username').value+"已经注册</span>";
}
else if(result ==-4)
{
document.getElementById('message').innerHTML = "<span style='color:red'>用户名不能为空</span>";
}
//将服务器返回的字符串写到页面中ID为message的区域
}
else
{
alert(xmlhttp_request.status);
}
}
}
//-->
</SCRIPT>
</HEAD>
<BODY>
<!--
接口 http://pass.kingsoft.com/ksgweb/jsp/login/uid.jsp?uid=
-->
请输入用户名：<input type="text" id="username" onblur="IDRequest();" />
<div id="message"></div>
</BODY>
</HTML>
