1.新建一个checkUser.htm文件
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>无标题页</title>
<script src="checkUser.js" type="text/javascript">
</script>
</head>
<body>
<h1>基于Ajax简单的数据验证</h1>
<hr />
<div>
<span>用户名:</span><input id="UserName" type="text" onblur="check();"/><span id="checkResult"></span>
</div>
<div>
<span>密 码:</span><input id="PassWord" type="password" />
</div>
</body>
</html>
2.新建一个checkUser.xml文件
<?xml version="1.0" encoding="utf-8" ?>
<User>
<UserName>admin</UserName>
<PassWord>admin</PassWord>
</User>
3.新建一个checkUser.js文件
var xmlHttp;
function createXMLHttpRequest()
{
if(window.ActiveXObject)
{
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if(window.XMLHttpRequest)
{
xmlHttp = new XMLHttpRequest();
}
}
function check()
{
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open("GET","checkUser.xml");
xmlHttp.send(null);
}
function handleStateChange()
{
if(xmlHttp.readyState == 4)
{
if(xmlHttp.status ==200)
{
checkResult();
}
}
}
function checkResult()
{
var xmlUser = xmlHttp.responseXML;
var xmlUserName = xmlUser.getElementsByTagName("UserName")[0];
if(document.getElementById("UserName").value == xmlUserName.childNodes[0].nodeValue)
document.getElementById("checkResult").innerHTML = "用户名已没被注册了!!!";
else
document.getElementById("checkResult").innerHTML = "用户名还没被注册!!!";
}
完成~~!