ajax.js

function ajax(params){
    var request = new XMLHttpRequest();
    var responseTimer;
    function handleError(e){
        console.error('Can\'t load data:', e.message, e);
        params.error && params.error(e);
    };
    request.open(params.method || 'GET', params.url, true);
    request.onreadystatechange = function(){
        if ( request.readyState === 4 ) {
            if ( request.status === 200 ) {
                if ( params.success ) {
                    try {
                        var json = JSON.parse(request.responseText);
                        params.success(json);
                    }
                    catch(e){
                        params.success(request.responseText);
                    }
                }
            }
            else {
                handleError({
                    message: 'Bad request',
                    data: request
                });
            }
            clearTimeout(responseTimer);
        }
    };
    request.send(params.data || null);
    responseTimer = setTimeout(function(){
        request.abort();
        handleError({
            message: 'Time is over'
        });
    }, 10000);
};