randomString: function () {
        var result = '';
        var words = 'qwertyuiopasdfghjklzxcvbnm';
        var max_position = words.length - 1;
        var i, position;
        for (i = 0; i < 5; ++i) {
            position = Math.floor(Math.random() * max_position);
            result = result + words.substring(position, position + 1);
        }
        return result;
    }