An XPCOM component implementing this interface can be exposed to web content as a property on the window. See Custom window properties are a snap in Firefox blog post for details.
An alternative way to expose an object to the web content is to add the property in response to the content-document-global-created notification.
jsval init( in nsIDOMWindow window );
- The window to which the global property is being attached.
The initialized global property. Ensure that you never return any internal XPCOM objects to untrusted code. It is also recommended to use __exposedProps__ to control which members are exposed.