[qwerty-клавиатура]

querystring = {
    parse: function(str, sep, eq) {
        eq = eq || '=';
        var obj = {};

        if (str) {
            var parts = str.split(sep || '&'), 
                i = 0, 
                j = parts.length;

            while (i < j) {
                var temp = parts[i++].split(eq);

                if (temp[0] !== '') {
                    obj[temp[0]] = temp[1] === undefined ? '' : decodeURIComponent(temp[1]);
                }
            }
        }

        return obj;
    },
    
    stringify: function(obj, sep, eq) {
        sep = sep || '&';
        eq = eq || '=';
        var out = [];

        for (var i in obj) {
            out.push( i + (obj[i] !== '' ? eq + encodeURIComponent(obj[i]) : '') );
        }

        return out.join(sep);
    }
};

// ...

// ajax.post('handler.php', {a: 'тест'}, {done: function(data) { console.log(data); }});
ajax = new (function(){
    /* options = {dataType: 'arraybuffer' || 'blob' || 'document' || 'json' || 'text', done: function(data) {...}, fail: function(code, text) {...} } */
    this.request = function(method, url, params, options) {
        options = options || {};
        var req = new XMLHttpRequest;
        req.responseType = options.dataType || '';
        
        if (options.done || options.fail) {
            req.onreadystatechange = function() {
                if (req.readyState == 4) {
                    if (req.status >= 200 && req.status < 300) {
                        if (options.done) {
                            options.done(req.response); 
                        }

                        return; 
                    }

                    if (options.fail) {
                        options.fail(req.status, req.statusText); 
                    }
                }
            } 
        }

        req.open(method, url);

        if (method.toLowerCase() == 'post') {
            req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
            params = querystring.stringify(params); 
        }
        
        req.send(params);
     };

    this.get = function(url, options) {
        this.request('GET', url, null, options);
    };

    this.post = function(url, params, options) {
        this.request('POST', url, params, options);
    };
})();