function doAJAX(url, params, callbackFx, formMethod) {
    if (window.XMLHttpRequest) {
		// Mozilla, Safari,...
        http_request = new XMLHttpRequest();
    } else {
        if (window.ActiveXObject) { // IE
            http_request = new ActiveXObject("Microsoft.XMLHTTP");
        }
    }
    http_request.onreadystatechange = callbackFx;
    if (formMethod == "GET") {
        http_request.open("GET", url + "?" + params, true);
        http_request.send(null);
    } else {
        http_request.open("POST", url, true);
        http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        http_request.setRequestHeader("Content-length", params.length);
        http_request.setRequestHeader("Connection", "close");
        http_request.send(params);
    }
}