An online school timetable is a digital version of a traditional paper-based timetable that students, teachers, and administrators can access through the internet. It typically includes information about classes, subjects, teachers, classrooms, and schedules. The online timetable can be accessed through a web portal or mobile application, which allows students and teachers to view their schedules and make changes as needed.

An online school timetable can have various features such as:

1. Class schedule: This feature allows students and teachers to view their class schedules, including the class name, subject, teacher, and room number.
2. Calendar view: This feature allows users to view their class schedules in a calendar format, making it easy to see when classes are scheduled.
3. Notifications: This feature allows users to receive notifications about changes in their schedules, such as a class being canceled or a room change.
4. Class materials: This feature allows teachers to share class materials, such as assignments and readings, with students.
5. Attendance: This feature allows teachers to track student attendance and view attendance reports.
6. Exam schedule: This feature allows students and teachers to view the exam schedule, including exam dates, times, and locations.
7. Mobile access: This feature allows users to access the timetable from their mobile devices, so they can check their schedule on the go.

An online school timetable can be integrated with other systems such as student information systems, and it can provide benefits such as ease of access, flexibility, and real-time updates.

An open-source online school timetable is a digital version of a traditional paper-based timetable that is built using open-source software and is freely available for anyone to use, modify, and distribute. There are several open-source options available for creating an online school timetable, some of them are:

1. OpenSIS: This is an open-source student information system that includes a timetable module, allowing students and teachers to view their class schedules, make changes, and share class materials.
2. Fedena: This is an open-source school management system that includes a timetable module, allowing students and teachers to view their class schedules, make changes, and track attendance.
3. OpenEMIS: This is an open-source education management information system that includes a timetable module, allowing students and teachers to view their class schedules, make changes, and share class materials.
4. OpenEduCat: This is an open-source school management system that includes a timetable module, allowing students and teachers to view their class schedules, make changes, and track attendance.
5. Orange: This is an open-source school management software that includes a timetable module, allowing students and teachers to view their class schedules, make changes, and track attendance.

These are some of the open-source options available for creating an online school timetable. These solutions are free to use, modify, and distribute. However, keep in mind that you may need additional resources and technical expertise to properly install and configure the system, as well as to maintain it.