Version:FormHelper 4.0.1
I have been able to receive callbacks to a function defined within a named closure (?) but the same format does not seem to work for asp-beforeSubmit. I noticed in the source that the callback happens through a callFunction() method which splits the callback name and retrieves it one part at a time. The beforeSubmit code though just calls windowoptions.beforeSubmit which fails with "window[options.beforeSubmit] is not a function".
Thanks!
James