in templates/ydotm/bootstrap3.js [684:714]
Dropdown.prototype.keydown = function (e) {
if (!/(38|40|27)/.test(e.keyCode)) return
var $this = $(this)
e.preventDefault()
e.stopPropagation()
if ($this.is('.disabled, :disabled')) return
var $parent = getParent($this)
var isActive = $parent.hasClass('open')
if (!isActive || (isActive && e.keyCode == 27)) {
if (e.which == 27) $parent.find(toggle).focus()
return $this.click()
}
var desc = ' li:not(.divider):visible a'
var $items = $parent.find('[role=menu]' + desc + ', [role=listbox]' + desc)
if (!$items.length) return
var index = $items.index($items.filter(':focus'))
if (e.keyCode == 38 && index > 0) index-- // up
if (e.keyCode == 40 && index < $items.length - 1) index++ // down
if (!~index) index = 0
$items.eq(index).focus()
}