The Event object is a static object in Navigator 4 and later that contains a large set of case-sensitive constant values you can use to test user- or system-generated events for keyboard modifiers and event types (see the modifiers and type properties of the event object). These constant values evaluate to mathematically related integers. Not all event types assigned a constant value are implemented as events in Navigator 4. This same object continues to be supported in Netscape 6, but only for backward compatibility with the Navigator 4 event capture syntax.