Verj.io apps are driven by events. Some events are part of the lifecycle of a 
Form or 
Page and some are triggered by end-user interaction.
You can attach 
Scripts to any event and every time an event is triggered this list of scripts is executed in order.
Events take place at three levels:
- Form for example, the Before Form event that runs when an end-user navigates to a Form for the first time.
- Page for example, the Before Page event that runs when an end-user navigates to a Page for the first time.
- Control for example, the On Click event that runs when an end-user clicks on a button in the browser.
These events run in the Verj.io Runtime Enviroment and are known as Server-side (or just server) events.
The JavaScript API allows your code to interact with the event using the event interface. Using event.owner you can access the specific Form, Page or Control that triggered the event.