function getXMLHTTP() {//oggettto XMLHttpRequest crossbrowser
	var s = ['undefined','MSIE 5','Microsoft','Msxml2','.XMLHTTP'];
	return ((typeof(XMLHttpRequest)!=s[0])?new XMLHttpRequest():
		((window.ActiveXObject)?new ActiveXObject(
			((navigator.userAgent.indexOf(s[1])!=-1)?s[2]:s[3])+s[4]):
		false));
}