I have a strange problem. I am using [jQuery weekcalendar](https://github.com/themouette/jquery-week-calendar) to show appointments in a calendar in the browser.

Everything is fine with Chrome. All my appointments are shown. In all other browsers, I only see the calendar, but not the appointments.

This is the link to my [calendar](http://www.slinder.ch/admin/admin/calendar/calendar.html).

Does anyone have an idea what is going on here? I don't know what code I should add to this question, as I have no idea where the problem is located. But the code is visible if you check the page source.