Where should UA insert text when the focus is changed in a keypress event handler?

Hi,

We're trying to figure out inside which element the editing operation must
be done when a keypress event handler changes the focused element /
selection for https://bugs.webkit.org/show_bug.cgi?id=81661.

Should it be done at wherever focus is after keypress event is dispatched?
Or whatever keypress event's target was?

DOM level 3 events doesn't seem to specify this behavior:
http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html#event-type-keypress

According to a fellow WebKit contributor, WebKit and Internet Explorer use
the current focused element whereas Firefox uses the event target.

Best,
Ryosuke Niwa
Software Engineer
Google Inc.