我们可以使用XML作为数据传送、沟通的格式，Ajax客户端若要发送XML，基本上就是将XML作为字符串，在POST请求时发送，例如：
*HelloAjax.js
view plaincopy to clipboardprint?
var xmlHttp;
function createXMLHttpRequest() {
if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
else if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
}
function prepareXML() {
var xml = "<skills>";
var options = document.getElementById("skills").childNodes;
for (var i = 0; i < options.length; i++) {
var option = options[i];
if (option.selected) {
xml = xml + "<skill>" + option.value + "<\/skill>";
}
}
xml = xml + "<\/skills>";
return xml;
}
function handleSkills() {
var xml = prepareXML();
var url = "Handler1.ashx?timeStamp=" + new Date().getTime();
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open("POST", url);
xmlHttp.setRequestHeader("Content-Type", "text/xml");
xmlHttp.send(xml);
}
var xmlHttp;
这是最常用的地址选择下拉框，包括三个下拉框，对应三个XML文件：
--------------------------------------------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<Provinces>
<Province ID="1" ProvinceName="北京市">北京市</Province>
<Province ID= ......
