网易异步传输模式ajax

function getXmlhttp()
{
var http_request;

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) {
window.alert("can't create XMLHttpRequest object.");
return null;
}
return http_request;
}

function loadAJAXTab(url,contentid){
var ocontent=getElement(contentid);
if(ajccache[url]==null) {
var xhttp=getXmlhttp();
xhttp.onreadystatechange=function(){
if(xhttp.readyState == 4 && (xhttp.status==200 || window.location.href.indexOf("http")==-1))
{
ocontent.innerHTML=xhttp.responseText;
ajccache[url]=ocontent.innerHTML;
}
}
xhttp.open("GET",url,true);
xhttp.send(null);
}else{
ocontent.innerHTML=ajccache[url];
}
}
window.onerror=function(){return true}

//xml.js
var xhr;
function getXHR()
{
try {
xhr=new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xhr=new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {
xh*=**lse;
}
}
if(!xhr&&typeof XMLHttpRequest!='undefined')
{
xhr=new XMLHttpRequest();
}

return xhr;
}

function openXHR(method,url,callback)
{
getXHR();
xhr.open(method,url);
xhr.onreadystatechange=function()
{
if(xhr.readyState!=4)return;
callback(xhr);
}
xhr.send(null);
}

function loadXML(method,url,callback)
{
getXHR();
xhr.open(method,url);
xhr.setRequestHeader("Content-Type","text/xml");
xhr.setRequestHeader("Content-Type","GBK");
xhr.onreadystatechange=function()
{
if(xhr.readyState!=4)return;
callback(xhr.respon***ML);
}
xhr.send(null);
}
//=================================================
function quote(xhr)
{
alert(xhr.responseText);
document.getElementById("xml").innerText=xhr.responseText;
}