GetSaveMode

Good morning everyone,

I need to pick up the Mark As Complete From Commitment button event and I'm using the code below:

Function preventAutoSave (econtext)
{
     Var eventArgs = ExecutionContextObj.getEventArgs ();
Alert (eventArgs);

     If (eventArgs.getSaveMode () == 58)
{
Alert(teste);
     }
}

But it is giving right error and is not displaying the alert with the event number.

I'm using CRM OnLine I do not know if this code was made for ONLINE