ServiceNow Script and Object Run on below order.

Client-Side Code:

1. onLoad Client scripts.
2. Client scripts and UI Policies that work onChange.
3. Client scripts that work onSubmit.

Server-Side Code:

1. Before business rules:
2. Before engines.
3. Before business rules:
4. The database operation (insert, update, delete).
5. After business rules:
6. After engines.
7. Email notifications.
8. After business rules.