Define the start of the week

[Schrank]

We germans like the monday for the first Day of the week, so I changed the Arrays for the Daynames and

// Calculate the first day to display (including the previous month)
date.setDate(1)
date.setDate(-(date.getDay()) + 2) <== here was a + 1

What we need is a config-variable (actually I didn't understand how to bring variables into the code) and a connection between the array key and this variable... And we need to bring this variable to the line of code pasted above

[Gargaj]

@Schrank I have a pull request that does just that: #8