写了一个简单的ajax操作类

<script language="javascript">
//-----------------------------------
// Description : ajax 简单操作类
// Author : no_mIss
// createTime : 2006.06.06
// lastUpdateTime : 2006.08.02
//-----------------------------------

function ajax(){
this.method;
this.url;
this.responsetype;
this.content;
var http_request = false;
this.getExecObj = function(reValue){
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("创建XMLHttpRequest对象实例失败.");
return false;
}

if(this.method.toLowerCase()=="get") {
http_request.open(this.method, this.url, true);
}
else if(this.method.toLowerCase()=="post") {
http_request.open(this.method, this.url, true);
http_request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
}
else {
window.alert("http请求类别参数错误。");
return false;
}
http_request.send(this.content);

var reTextResponse = function() {
if (http_request.readyState == 4) {
if (http_request.status == 200) {
reValue(http_request.responseText);
} else {
alert("页面有异常。");
}
}
}
var reXMLResponse = function() {
if (http_request.readyState == 4) {
if (http_request.status == 200) {
reValue(http_request.responseXML);
} else {
alert("页面有异常。");
}
}
}

if(this.responsetype.toLowerCase()=="text") {
http_request.onreadystatechange = reTextResponse;
}
else if(this.responsetype.toLowerCase()=="xml") {
http_request.onreadystatechange = reXMLResponse;
}
else {
window.alert("参数错误。");
return false;
}
}
}

// 调用方法
var _ajax = new ajax()
_ajax.method = "post";//是get还是post
_ajax.url = "http://aaa.com/a.asp"; //请求的地址
_ajax.responsetype = "text";//处理返回内容的类型
_ajax.content = "id=1";//发送的内容
_ajax.getExecObj(function(str){document.getElementById("aaa").innerHTML = str});//对返回值处理

</script>
<div id="aaa"></div>