能否给个XMLHTTP异步响应的例子

本站讨论了XMLHTTP在表示层的应用，我觉得和HTTP配合起来可以解决项目中很多问题。但大家在阐述时的例子都是同步的，自己去找异步的例子没找到，所以偷懒问一下斑竹，能否给个异步的例子的sample code

摘自Microsoft XML SDK 2.6 - XML Reference 一段例子：
The following JScript/HTML example specifies the the handler HandleStateChange gets called when an XMLHttpRequest object's readyState property changes. A button on a page is enabled when readyState indicates that all data has been received (readystate == 4).

<script>
var xmlhttp=null;
function PostOrder(xmldoc);
{
  var xmlhttp = new ActiveXObject("Msxml2.XMLHttp");;
  xmlhttp.Open("POST", "http://myserver/orders/processorder.asp", false);; 
  xmlhttp.onreadystatechange= HandleStateChange;
  xmlhttp.Send(xmldoc);;
  myButton.disabled = true;
}
function HandleStateChange();
{
  if (xmlhttp.readyState == 4);
  {
    myButton.disabled = false;
    alert("Result = " + xmlhttp.responseXML.xml);;
  }
}
</script>

写错了.

xmlhttp.Open("POST", "http://myserver/orders/processorder.asp", false);

第三个参数是isAysnc,表示是否异步.这里应该是true才对。