The implementation status of spatial navigation in Web engines

To support the heuristic algorithm in the Web, we need to implement the codes into Web engines.

Blink

Spatial Navigation issue list in Chromium Bugs
- https://bugs.chromium.org/p/chromium/issues/list?can=1&q=spatial%20navigation

Spatial Navigation issue list in WebKit Bugzilla
- http://bit.ly/2z0QlDl
[webkit-dev] RFC: Spatial Navigation feature for WebCore (2010/01/15)
- https://lists.webkit.org/pipermail/webkit-dev/2010-January/011339.html
Bug 18662 - Extend keyboard navigation to allow directional navigation (2008/04/21)
- https://bugs.webkit.org/show_bug.cgi?id=18662

Interacting with TV remote controls (2016/06/24)
- https://developer.mozilla.org/en-US/docs/Mozilla/Firefox_OS_for_TV/Interacting_with_TV_remote_controls
The relevant codes in Gecko
- https://dxr.mozilla.org/mozilla-central/search?q=spatial+navigation&redirect=false
Does Spatial Navigation Exist for firefox?
- https://support.mozilla.org/ko/questions/955214 (2013/04/03)
Keyboard navigation proposal for Mozilla (2014/09/15)
- https://lists.w3.org/Archives/Public/w3c-wai-ua/2004JulSep/0040.html
Firefox - hook snav up to browser (2013/08/02)
- https://bugzilla.mozilla.org/show_bug.cgi?id=443043

Focus navigation with keyboard, gamepad, and accessibility tools (2017/08/02)
- https://docs.microsoft.com/en-us/windows/uwp/input-and-devices/managing-focus-navigation
Custom keyboard interactions (2017/08/24)
- https://docs.microsoft.com/en-us/windows/uwp/input-and-devices/custom-keyboard-interactions
TVJS API (2017/07/12)
- https://github.com/Microsoft/TVHelpers/wiki
Using DirectionalNavigation (2016/06/25)
- https://github.com/Microsoft/TVHelpers/wiki/Using-DirectionalNavigation

Tweaking Spatial Navigation for TV Browsing (2017/09/14)
- https://developer.vewd.com/display/OTV/Tweaking+Spatial+Navigation+for+TV+Browsing
Spatial Navigation and Opera (2008/02/13)
- https://blog.codinghorror.com/spatial-navigation-and-opera/

react-spatial-tv-navigation (2017/04/11)
- https://github.com/SatadruBhattacharjee/react-spatial-tv-navigation

Creating TV Navigation (Android)
- https://developer.android.com/training/tv/start/navigation.html
The Focus Engine Controls Focus (Apple)
- https://developer.apple.com/library/content/documentation/General/Conceptual/AppleTV_PG/WorkingwiththeAppleTVRemote.html
Tizen (2015/10/28)
- https://bugs.tizen.org/browse/TT-211?jql=text%20~%20%22spatial%20navigation%22
QT WebKit (2013/02/08)
- https://bugreports.qt.io/browse/QTWEBKIT-271?jql=text%20~%20%22spatial%20navigation%22
The summary of Spatial Navigation (2015/04/02, Florian)
- https://florian.rivoal.net/blog/2015/04/controlling-spatial-navigation/