function Ajax(recvType){
var aj=new Object();
aj.recvType=recvType ? recvType.toUpperCase() : 'HTML'; //向形参中传递的文件类型
aj.targetUrl='';
aj.sendString='';
aj.resultHandle=null;
/*创建XMLHttpRequest对象*/
aj.createXMLHttpRequest=function(){
var xmlHttp = false;
if(window.XMLHttpRequest){ //在非IE中创建XMLHttpRequest对象
xmlHttp = new XMLHttpRequest();
}else if(window.ActiveXObject){
try{
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); //按新版IE创建
}catch(error1){ //创建失败
try{
xmlHttp = new ActiveXobject("Microsoft.XMLHttp"); //按老版IE创建
}catch(error2){ //创建失败
xmlHttp = false;
}
}
}
return xmlHttp;
}
aj.XMLHttpRequest=aj.createXMLHttpRequest();
/*处理服务器的响应*/
aj.processHandle=function(){
if(aj.XMLHttpRequest.readyState == 4){
if(aj.XMLHttpRequest.status == 200){
if(aj.recvType=="HTML")
aj.resultHandle(aj.XMLHttpRequest.responseText);
else if(aj.recvType=="XML")
aj.resultHandle(aj.XMLHttpRequest.responseXML);
}
}
}
/*定义使用get方法传递的方法*/
aj.get=function(targetUrl, resultHandle){
aj.targetUrl=targetUrl;
if(resultHandle!=null){
aj.XMLHttpRequest.onreadystatechange=aj.processHandle;
aj.resultHandle=resultHandle;
}
if(window.XMLHttpRequest){
aj.XMLHttpRequest.open("get", aj.targetUrl);
aj.XMLHttpRequest.send(null);
}else{
aj.XMLHttpRequest.open("get", aj.targetUrl, true);
aj.XMLHttpRequest.send();
}
}
/*定义使用post方法传递的方法*/
aj.post=function(targetUrl, sendString, resultHandle){
aj.targetUrl=targetUrl;
if(typeof(sendString)=="object"){
var str="";
for(var pro in sendString){
str+=pro+"="+sendString[pro]+"&";
}
aj.sendString=str.substr(0, str.length-1);
}else{
aj.sendString=sendString;
}
if(resultHandle!=null){
aj.XMLHttpRequest.onreadystatechange=aj.processHandle;
aj.resultHandle=resultHandle;
}
aj.XMLHttpRequest.open("post", targetUrl);
aj.XMLHttpRequest.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
aj.XMLHttpRequest.send(aj.sendString);
}
return aj;
}

<script src="ajax.js"></script>
<script language="javascript" type="text/javascript">
var ajax=Ajax();
/*get使用方式*/
ajax.get("server.php?name=zhangsan&phone=778", function(data){
alert(data); //data为从服务器端读取的数据
});
/*第一种post使用方式*/
/* ajax.post("server.php", "name=ligang&phone=222", function(data){
alert(data);
});
*/
/*第二种post使用方式*/
/* ajax.post("server.php", {name:"tom",phone:"456"},function(data){
alert(data);
});
*/
</script>
server.php
<?php
header("Content-type:text/html;charset=gb2312");
$str = "姓名：{$_GET["name"]}\n电话：{$_GET["phone"]}";
echo $str;
?>