ONLYOFFICE 7.0: online forms, password protection in sheets, collaboration improvements and much more
ONLYOFFICE 7.0 released

Add event before clicking save

I want to call an event before clicking save. How can I do this.

There is no such event available. Full list of events can be found here:

However, if you use another type of forcesave (request to the command service ONLYOFFICE Api Documentation - Command service), you can create your own save button in your application frame and add your own custom events to it.