Note:
This event does not distinguish between submissions that are initiated by instances of clicking buttons, or submissions made to different URLs. Any script that needs to make these distinctions must include a script to determine which button was clicked. In general, the postSubmit event is conceptually similar to the postSave event and serves a similar purpose.
You can use this event to perform actions immediately after the form data is submitted. For example, you can create a script on the postSubmit event to display confirmation that the submission performed successfully.
See also 

postSubmit event