利用AJAX实现鼠标悬浮获取值的代码

!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>
meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
title>鼠标悬浮测试/title>
/head>
script type="text/javascript" language="javascript">
var xmlHttp;
function createXMLHttpRequest(){
if(window.ActiveXObject){
xmlHttp = new ActiveXObject("microsoft.XMLHTTP");
}
else if(window.XMLHttpRequest){
xmlHttp = new XMLHttpRequest();
}
}
function sendRequest(t){
var id = t.id
createXMLHttpRequest();
var url = "mouseover_check.php?page=" +t.id ;
xmlHttp.onreadystatechange = callback;
xmlHttp.open('GET',url,true);
xmlHttp.send(null);
}
function callback(){
if(xmlHttp.readyState == 4){
if(xmlHttp.status == 200){
document.getElementById("show").innerHTML = xmlHttp.responseText;
}
}
}

/script>
body>
p>
input type="text" value="here" id="1" onmouseover="sendRequest(this)" />
/p>
p>br/>
input type="text" value="haha" id="2" onmouseover="sendRequest(this)" />
/div>
/p>
p>/p>
span id="show">/span>
/body>
/html>

?php
header("Content-type:text/html;charset=gb2312");
header("cache-control:no-cache,must-revalidate");
$name = $_GET['page'];
if($name == '1'){
echo "111";
}
else{
echo "222";
}
?>