In the previous versions

EventClickHandling Handling of a click on a calendar event. UserActionHandling UserActionHandling.JavaScript
FreetimeClickHandling Handling of a click on a free-time slot. UserActionHandling UserActionHandling.JavaScript
JavaScriptEventAction JavaScript code that should be executed when the user clicks on a calendar event (provided that EventClickHandling is set to JavaScript). The string "{0}" will be replaced with an event ID. string "alert('{0}');"
JavaScriptFreeAction JavaScript code that should be executed when the user clicks on a free-time slot (provided that FreetimeClickHandling is set to JavaScript). The string "{0}" will be replaced with the date and time specified in the standard format produced by DateTime.ToString("s") - e.g. "2006-05-15T07:00:00". string "alert('{0}');"

Now in the current versions these dont exist!!

A logical version would be EventClickHandling = Enums.UserActionHandling.JavaScript

And then set up the javascript ..

But no the API does not support the previous {0} substitutions, and there is NO documentation, and NO Source..

BROKEN!!