var getJSON = function (url, successHandler, errorHandler) {
    var xhr = typeof XMLHttpRequest != 'undefined' ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP');
    xhr.open('get', url, true);

    xhr.onreadystatechange = function () {
        var status;
        var data;

        if (xhr.readyState == 4) { // `DONE`
            status = xhr.status;
            if (status == 200) {
                data = JSON.parse(xhr.responseText);
                successHandler && successHandler(data);
            } else {
                errorHandler && errorHandler(status);
            }
        }
    };
    xhr.send();
};