ajax读取txt

DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" >
< html >
< head >
< title > Ajax Hello World title >
< script type ="text/javascript" >
var xmlHttp;

function createXMLHttpRequest(){
if (window.ActiveXObject){
xmlHttp = new ActiveXObject( " Microsoft.XMLHTTP " );
}
else if (window.XMLHttpRequest){
xmlHttp = new XMLHttpRequest();
}
}

function startRequest(){
createXMLHttpRequest();
try {
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open( " GET " , " data.txt " , true );
xmlHttp.send( null );
} catch (exception){
alert( " 您要访问的资源不存在! " );
}
}

function handleStateChange(){
if (xmlHttp.readyState == 4 ){
if (xmlHttp.status == 200 || xmlHttp.status == 0 ){
// 显示返回结果
alert( " responseText's value: " + xmlHttp.responseText);
}
}
}
script >
head >
< body >
< div >
< input type ="button" value ="return ajax responseText's value"
onclick ="startRequest();" />
div >
body >
html >