var xmlhttp = false;

try {
	xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
	try {
		xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
	} catch (E) {
		xmlhttp = false;
	}
}

if (!xmlhttp && typeof XMLHttpRequest != 'undefined') {
	xmlhttp = new XMLHttpRequest();
}