var xhttp = null;

if(window.XMLHttpRequest){ //IE7, Mozilla ,Firefox 等浏览器内置该对象

 xhttp = new XMLHttpRequest();
 
}else if(window.ActiveXObject){ //IE6、IE5

 try{ xhttp = new ActiveXObject("Msxml2.XMLHTTP");} catch (e){ ; }
 
 if( xhttp == null) try { xhttp = new ActiveXObject("Microsoft.XMLHTTP");} catch (e){; }
 
}

function DedeAjax(WiteOKFunc){ //WiteOKFunc 为异步状态事件处理函数

//xmlhttp和xmldom对象
this.xhttp = null;
this.xdom = null;

//post或get发送数据的键值对
this.keys = Array();
this.values = Array();
this.keyCount = -1;

//http请求头
this.rkeys = Array();
this.rvalues = Array();
this.rkeyCount = -1;
//请求头类型
this.rtype = 'text';

//初始化xmlhttp
if(window.XMLHttpRequest){//IE7, Mozilla ,Firefox 等浏览器内置该对象
    this.xhttp = new XMLHttpRequest();
}else if(window.ActiveXObject){//IE6、IE5
    try { this.xhttp = new ActiveXObject("Msxml2.XMLHTTP");} catch (e) { }
    if (this.xhttp == null) try { this.xhttp = new ActiveXObject("Microsoft.XMLHTTP");} catch (e) { }
}
this.xhttp.onreadystatechange = WiteOKFunc;
//rs: responseBody、responseStream、responseXml、responseText

//以下为成员函数
//--------------------------------

//初始化xmldom
this.InitXDom = function(){
 var obj = null;
 if (typeof(DOMParser) != "undefined") { // Gecko、Mozilla、Firefox
   var parser = new DOMParser();
   obj = parser.parseFromString(xmlText, "text/xml");
 } else { // IE
   try { obj = new ActiveXObject("MSXML2.DOMDocument");} catch (e) { }
   if (obj == null) try { obj = new ActiveXObject("Microsoft.XMLDOM"); } catch (e) { }
 }
 this.xdom = obj;
};

//增加一个POST或GET键值对
this.AddKey = function(skey,svalue){
this.keyCount++;
this.keys[this.keyCount] = skey;
this.values[this.keyCount] = escape(svalue);
};

//增加一个Http请求头键值对
this.AddHead = function(skey,svalue){
this.rkeyCount++;
this.rkeys[this.rkeyCount] = skey;
this.rvalues[this.rkeyCount] = svalue;
};

//清除当前对象的哈希表参数
this.ClearSet = function(){
this.keyCount = -1;
this.keys = Array();
this.values = Array();
this.rkeyCount = -1;
this.rkeys = Array();
this.rvalues = Array();
};

//发送http请求头
this.SendHead = function(){
if(this.rkeyCount!=-1){ //发送用户自行设定的请求头
  for(;i<=this.rkeyCount;i++){
   this.xhttp.setRequestHeader(this.rkeys[i],this.rvalues[i]);
  }
 }
　if(this.rtype=='binary'){
  this.xhttp.setRequestHeader("Content-Type","multipart/form-data");
 }else{
  this.xhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
 }
};

//用Post方式发送数据
this.SendPost = function(purl){
var pdata = "";
var i=0;
this.state = 0;
this.xhttp.open("POST", purl, true);
this.SendHead();
 if(this.keyCount!=-1){ //post数据
  for(;i<=this.keyCount;i++){
   if(pdata=="") pdata = this.keys[i]+'='+this.values[i];
   else pdata += "&"+this.keys[i]+'='+this.values[i];
  }
 }
 this.xhttp.send(pdata);
};

//用GET方式发送数据
this.SendGet = function(purl){
var gkey = "";
var i=0;
this.state = 0;
if(this.keyCount!=-1){ //get参数
  for(;i<=this.keyCount;i++){
   if(gkey=="") gkey = this.keys[i]+'='+this.values[i];
   else gkey += "&"+this.keys[i]+'='+this.values[i];
  }
  if(purl.indexOf('?')==-1) purl = purl + '?' + gkey;
  else  purl = purl + '&' + gkey;
 }
this.xhttp.open("GET", purl, true);
this.SendHead();
 this.xhttp.send();
};

} // End Class DedeAjax

<script language='javascript'  src='dedeajax.js'></script>
<script language='javascript'>
function WiteOK()
{
  var myinfo = document.getElementById("myinfo");
   if(myajax.xhttp.readyState == 4){
       if(myajax.xhttp.status == 200){
           myinfo.innerHTML = myajax.xhttp.responseText;
       }
   }
}
var myajax = new DedeAjax(WiteOK);
myajax.AddKey("key1","----------------------------");
myajax.SendPost("test.php");

</script>

<div id='myinfo'><div>

<?
header("Content-Type: text/html; charset=gb2312");
echo $_POST['key1'];
?>

this.AddKey = function(skey,svalue){
  this.keyCount++;
  this.keys[this.keyCount] = skey;
  this.values[this.keyCount] = svalue;//escape(svalue);
};

//unicode url编码转gbk编码函数
function Unicode2Gbk($str)
{
//载入对照词典
if(!isset($GLOBALS['GbkUniDic']))
{
  $ds = file("./data/gbk_unicode.dic");
  foreach($ds as $l){
   $GLOBALS['GbkUniDic'][hexdec('0x'.substr($l,0,4))] = substr($l,5,4);
  }
 }
 //处理字符串
 $glen = strlen($str);
 $okstr = "";
 for($i=0; $i < $glen; $i++)
 {
   if( $glen-$i > 4){
     if($str[$i]=='%' && $str[$i+1]=='u'){
        $uni = hexdec('0x'.substr($str,$i+2,4));
        if(isset($GLOBALS['GbkUniDic'][$uni])){
         $uni = $GLOBALS['GbkUniDic'][$uni];
         $okstr .= chr(hexdec(substr($uni,0,2))).chr(hexdec(substr($uni,2,2)));
        }
        else $okstr .= "&#{".hexdec("0x".$uni).";";
        $i = $i+5;
     }
     else $okstr .= $str[$i];
   }
   else $okstr .= $str[$i];
 }
 return $okstr;
}

<?
header("Content-Type: text/xml; charset=gb2312");
echo '<'.'?'."xml version=\"1.0\" encoding=\"gb2312\" ".'?'.">
<myhome>
 <item sex=\"男\">我是小一</item>
 <item sex=\"女\">我是小二</item>
</myhome>
";
?>

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>ajax测试</title>
</head>
<body onload="WiteLoadDocument()">
<script language='javascript'  src='dedeajax.js'></script>
<script language='javascript'>
var myajax = new DedeAjax(WiteOK);
function WiteOK()
{
  var myinfo = document.getElementById("myinfo");
  var mydom = null;
  myinfo.innerHTML = "以下是处理结果：<br/>";
  if(myajax.xhttp.readyState == 4){
    mydom = myajax.xhttp.responseXml;
    alert(mydom);
  }
}
function WiteLoadDocument()
{
  myajax.SendGet("test2.php");
}
</script>
<div id='myinfo'><div>
</body>
</html>

function WiteOK()
{
  var myinfo = document.getElementById("myinfo");
  var mydom = null;
  myinfo.innerHTML = "以下是处理结果：<br/>";
  if(myajax.xhttp.readyState == 4){
    mydom = myajax.xhttp.responseXml;
    var nodeList = mydom.selectNodes("/myhome/item");
    var mynode = null;
    var myatt = null;
    var mysex = "";
    for(i=1;i<=nodeList.length;i++)
    {
      mynode = nodeList[i-1];
      for(j=0;j < myinfo.attributes.length;j++)
      {
        if(!mynode.attributes[j]) break;
        myatt = mynode.attributes[j];
        if(myatt.name=='sex') mysex = myatt.value;
      }
      myinfo.innerHTML += "我是："+mynode.text+"，我的性别是："+ mysex +"<br/>";
    }
  }
}

以下是处理结果：
我是：我是小一，我的性别是：男
我是：我是小二，我的性别是：女