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Re: [DOM Level 3 Events] optionality of the capture argument in addEventListener/removeEventListener

From: Jonas Sicking <jonas@sicking.cc>
Date: Wed, 29 Sep 2010 20:31:24 -0700
Message-ID: <AANLkTikWDcyrc-zLg=B5JRNWvuE9qxRzAicpfN_0tuYA@mail.gmail.com>
To: Olli@pettay.fi
Cc: Sergey Ilinsky <sergey@ilinsky.com>, www-dom@w3.org
On Wed, Sep 29, 2010 at 10:04 AM, Olli Pettay <Olli.Pettay@helsinki.fi> wrote:
> On 09/24/2010 11:48 PM, Jonas Sicking wrote:
>>
>> On Fri, Sep 24, 2010 at 12:17 PM, Sergey Ilinsky<sergey@ilinsky.com>
>>  wrote:
>>>
>>> There are modern browsers that made 3rd argument in the
>>> addEventListener/removeEventListener be optional. Is this a legal step?
>>> If I understand correctly, specification requires 3rd argument to be
>>> passed,
>>> thus the new behaviour not backed by the change
>>> in specification only destabilizes web as a platform.
>>> Personally, I like the behaviour, but cannot use it as long as not every
>>> browser does that.
>>
>> Currently it does not appear to be legal based on my reading of the
>> latest editor drafts. However I would love to change that. It wouldn't
>> be a big change in the spec, just stick [optional] in front of the
>> useCapture argument, and it should be no problem as far as backwards
>> compatibility goes. And at least in gecko it would be trivial to
>> implement.
>>
>> The only problem I can think of is that it means that people might
>> write pages that only works in newer browsers, however that is true
>> for any new feature added.
>>
>> / Jonas
>
> I don't support this kind of change.
> It happens way too often that people don't think about the phase, and that
> leads to bugs.

I don't think requiring the last argument is helping a whole lot with
that right now. I've heard multiple times developers say:

"I don't know why I have to specify the last 'false' value, but I have
to do that everywhere when I call addEventListener".

/ Jonas
Received on Thursday, 30 September 2010 03:32:18 GMT

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