Re: ISSUE-137 (IME-keypress): Should keypress events fire when using an IME? [DOM3 Events]


Currently, Firefox doesn't fire any key events (keydown, keyup and 
keypress) during IME composition.  There are some reasons:

1. Most firefox code handles key events without IME composition state 
check. (This is our internal reason, though) Therefore, if we would fire 
key events during composition, we would need to fix very many code.

2. Web application developers cannot check IME composition state 
directly.  If they needed to check it, they needed to listen 
compositionstart and compositionend events and make a bool variable. 
Therefore, if web developers handled key events without IME state check, 
IME users couldn't use some web applications.

3. Some web developers may not know well about IME behavior. Their web 
applications might break IME behavior by handling key events.

I'd like to *suggest* that key events shouldn't be fired during IME 
composition, especially for #3.  If web developers want to know the 
timing of updating composition string, they can use compositionupdate or 
textinput. I think that these events are better for the purpose since 
IME composition string can be updated by clicking on candidate window, 
i.e., it doesn't cause key events.


On 2010/10/06 15:16, Web Applications Working Group Issue Tracker wrote:
> ISSUE-137 (IME-keypress): Should keypress events fire when using an IME? [DOM3 Events]
> Raised by: Doug Schepers
> On product: DOM3 Events
> Hallvord R. M. Steen<>:
> [[
> current spec text says about the keypress event:
>> This event type shall be generated after the keyboard mapping
>> but before the processing of an input method editor, normally
>> associated with the dispatching of a compositionstart, compositionupdate,
>> or compositionend event.
> I think this is wrong, if an IME is actively processing the input no
> keypress event should fire.
> ]]

Masayuki Nakano <>
Manager, Internationalization, Mozilla Japan.

Received on Tuesday, 9 August 2011 08:58:19 UTC