function getXMLHttpRequest(){
	if(window.ActiveXObject) {
		try{
		return new ActiveXObject("Msxml2.XMLHTTP");
		} catch(e) {
			try {
				return new ActiveXObject("Microsoft.XMLHTTP");
			} catch(e1) { return null; }
		}
	} else if(window.XMLHttpRequest) {
		return new XMLHttpRequest();
	} else {
		return null;
	}
}
function ajaxRequest(pageUrl, params, afterFunction, requestMethod)
{
	var xmlRequest = getXMLHttpRequest();

	if (requestMethod == null) {
		xmlRequest.open("GET",pageUrl,true);
	} else if(requestMethod == "POST") {
		xmlRequest.open("POST",pageUrl,true);
	}
	xmlRequest.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
	xmlRequest.setRequestHeader("Cache-Control","no-cache, must-revalidate");
	xmlRequest.setRequestHeader("Pragma","no-cache");
	if (afterFunction != null)
	{
		xmlRequest.onreadystatechange = function() {CallBack(xmlRequest,afterFunction);};
	}
	
	xmlRequest.send(params);
}
function CallBack(xmlRequest,afterFunction)
{
	if (xmlRequest == null || xmlRequest.readyState != 4) return;
	var xmlStr = xmlRequest.responseText
	if (afterFunction != null)
	{
		afterFunction(xmlStr);
	}
}