GETTING YOUR HEAD around the whole script trigger concept is quite challenging. Mislav Kos developed a visual that ties it all together:
There are quite a few nuances in how FileMaker script triggers function. Two of the more straightforward ones are the sequence that script triggers evaluate in (e.g. OnObjectKeystroke fires before OnLayoutKeystroke) and the timing of a script as compared to the event that triggered it (i.e. pre- vs post-event triggering).For me, the difficulty with these two attributes isn’t comprehension; it’s memorization. I find myself looking this stuff up over and over again. So, to make it easier to remember, I mocked up the following diagram. Hopefully it has some use for you as well.
He also linked an updated pdf containing a more detailed reference.