function GetXmlHttpObject(){
	var objXMLHttp = null;
	if( window.XMLHttpRequest){
		objXMLHttp = new XMLHttpRequest();
	}else if( window.ActiveXObject){
		objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP");
	}
	return objXMLHttp;
}

function AjaxAction( where, url){
	var xmlHttp = new GetXmlHttpObject()
	if(xmlHttp==null){
		return;
	}
	var bar = '<img src="images/loading.gif" align="absmiddle" /> &#272;ang t&#7843;i d&#7919; li&#7879;u';
	document.getElementById( where).innerHTML = bar
	xmlHttp.onreadystatechange= function(){
		if(xmlHttp.readyState==4 || xmlHttp.readyState == 200){
			document.getElementById( where).innerHTML = xmlHttp.responseText
		}
	}
	// Set header so the called script knows that it's an XMLHttpRequest
	//xmlHttp.setRequestHeader("X-Requested-With", "XMLHttpRequest");
	xmlHttp.open( "GET", url, true);
	xmlHttp.send(null);
}