Input: remotes and gamepads

Every platform’s input arrives as DOM keyboard events, because SDL has already normalised the hardware:

Hardware	Arrives as
tvOS Siri Remote	arrows, Enter (select), Escape (Menu)
Android TV / Fire TV remote	arrows, Enter (D-pad centre), AC Back, media keys
macOS / Linux keyboard	a keyboard
Game controllers	keys, until you claim them (below)

Each becomes a keydown / keyup with key, code and the legacy keyCode that TV frameworks still key on — Blits and Lightning read 37–40 for the arrows, 13 for enter and 8 for back.

window.addEventListener('keydown', (e) => {
  switch (e.key) {
    case 'ArrowRight': focusNext(); break
    case 'Enter':      activate();  break
    case 'Escape':     goBack();    break   // tvOS Menu, Android Back
  }
})

Gamepads

Gamepads are the W3C Gamepad API in the standard mapping. gamepadconnected and gamepaddisconnected are trusted GamepadEvents at window, fired as tasks that a pause holds rather than drops — a controller connecting is a fact the page needs after it resumes.

window.addEventListener('gamepadconnected', (e) => {
  console.log(e.gamepad.index, e.gamepad.id)
})

function frame () {
  const [pad] = navigator.getGamepads()
  if (pad?.buttons[0].pressed) jump()
  requestAnimationFrame(frame)
}

The claim is one-way and process-wide

Your app’s first navigator.getGamepads() claims the gamepads for the whole process. From then on, gamepad buttons and sticks produce no key events, and whatever keys they were holding are released. Keyboards and remotes are unaffected, and there is no way back.

This is what you want if you read pads directly — and a surprise if you called getGamepads() to feature-detect. Don’t probe with it.

Input follows focus

Keys go to the focused browsing context and to nothing else. When a launcher calls focus() on an <iframe>, the launcher stops receiving input and the instance starts. A focus switch releases keys that were held, the way a controller disconnecting mid-press does, so no context is left with a key down it will never see go up.

Leaving the app

window.close() calls the host’s exit path where the host defines one — the Android host finishes the activity. On tvOS, the Menu button at the app’s root does not yet exit to the Home screen; the JavaScript-visible way out is the app’s own window.close() call rather than a guess about Back.