Events

If you have ever developed with JavaScript or Java Swing, you should be familiar with the idea of event-driven programming. You write handlers that respond to interface events as they occur. The events may or may not have been triggered by user interaction.

In the Lightning Component framework, events are fired from JavaScript controller actions. Events can contain attributes that can be set before the event is fired and read when the event is handled.

Events are declared by the aura:event tag in a .evt resource, and they can have one of two types: component or application. The event type is set by either type="COMPONENT" or type="APPLICATION" in the aura:event tag.