kai.infotren/common/items.js

var currentIndex = 0

function nav(offset) {
	var items = document.querySelectorAll('.items:not(.disabled)')

	currentIndex += offset
	if (currentIndex < 0) {
		currentIndex += items.length
	}
	if (currentIndex >= items.length) {
		currentIndex -= items.length
	}
	items[currentIndex].focus()
	items[currentIndex].addEventListener('keydown', handleKeyDown)
}

function handleKeyDown(e) {
	if (e.target.classList.contains('items')) {
		switch (e.key) {
			case 'ArrowUp':
				e.preventDefault()
				e.stopPropagation()
				nav(-1)
				break
			case 'ArrowDown':
				e.preventDefault()
				e.stopPropagation()
				nav(1)
				break
		}
	}
}

window.addEventListener('load', function (e) {
	// Select first item
	var items = document.querySelectorAll('.items:not(.disabled)')
	if (items.length > 0) {
		items[0].focus()
		items[0].addEventListener('keydown', handleKeyDown)
	}

	document.body.addEventListener('keydown', handleKeyDown)
})