function createXHR() {

    var request;

    if (typeof (XMLHttpRequest) == 'undefined') {

        request = new ActiveXObject('Microsoft.XMLHTTP');

    } else {

        request = new XMLHttpRequest();

    }

    return request;

}

var xhr = createXHR();

function ajax(method, url, isAsync, data, fnsuccess, fnerror) {

    xhr.open(method, url, isAsync);

    if (method.toLocaleLowerCase() == 'post') {

        xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

    }

    xhr.onreadystatechange = function () {

        if (xhr.readyState == 4) {

            if (xhr.status == 200) {

                return fnsuccess(xhr.responseText);

            } else {

                return fnerror();

            }

        }

    };

    xhr.send(data);

}

function get(url, fnsuccess) {

    return ajax("get", url, true, null, fnsuccess, null);

}

function post(url, data, fnsuccess) {

    return ajax("post", url, true, data, fnsuccess, null);

}