Keyboard Events and Accessibility in Navigator

[JayPanoz]

At the moment you can tab onto anchors in iframe’s content documents but using the Enter key doesn’t trigger a click, which is an accessibility concern. It should therefore be taken into account in event handling.

Of course we may also want to treat column offset when tabbing in paginated layout as a side-effect, and possibly filter the focusable elements whose keyboard events we don’t want to prevent – as some may be problematic security-wise.