Thanks for the fast reply!
I had something else in mind. I am sorry for my bad English. I mean updating the Quantity and Total values in the Event add cart section in the frontend Event page. I can see a Javascript function that is responsible for this action, but it doesn’t work. I click on + in the ticket purchase form, the number of tickets in the field is increased by 1. But at the bottom of the form, the Quantity and Total values are 0. You can see the screenshot there.
Thanks!