Basic concept of spatial navigation

Preconditions of Spatial Navigation

SpatNav Spec is too complicated, so we need to list up the preconditions for the spec.

• The default container is the document element of a browsing context’s document (not limited to the top-level browsing context) or a scroll container.
• Scrollable area is focusable.
• Candidates are focusable elements which are visible within the scrollport of a certain container.

Points to be considered

• Does the spatnav container delegates focus to the element inside it?
• Do candidates need to consider the invisible focusable element within the spatnav container?

Core Features of Spatial Navigation

1. Spatial focus navigation heuristic

   • The basic spatial navigation behavior supported by browser.

2. Activating Spatial Navigation: 'spatial-navigation'

3. Creating container: 'spatnav-container'

4. NavigationEvent

   • Cover the edge cases of SpatNav heuristic
   • SpatNav customization

5. JS API

   • Cover the edge cases of SpatNav heuristic
   • SpatNav customization (not sure..)

Points to be considered

• Is directly moving the focus to the invisible focusable within the scrollable spatanv container the core feature?