try {
	// Firefox, Opera 8.0+, Safari
	xmlHttp=new XMLHttpRequest();
}
catch (e) {
	// Internet Explorer
	try {
		xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
	}
	catch (e) {
		try {
			xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
		}
		catch (e) {
			xmlHttp=null;
		}
	}
}