gistfile1.txt

beforeShowDay: function(date) {
                    var enabled = true;

                    disabledDates.forEach(function(disabledDate){
                        var from = new Date(disabledDate['from']);
                        var to = new Date(disabledDate['to']);

                        from.setHours(0);
                        from.setMinutes(0);
                        from.setSeconds(0);

                        to.setHours(23);
                        to.setMinutes(59);
                        to.setSeconds(59);

                        if (date < from || date > to) {
                            enabled = true;
                        } else {
                            enabled = false;
                        }
                    });

                    return [enabled, '', ''];
                }