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Re: localStorage Event

From: Jared Morse <jarcoal@gmail.com>
Date: Fri, 29 Jan 2010 11:13:25 -0800
Message-ID: <19e6d9a31001291113p1117b3b3p2b5e13383a376bae@mail.gmail.com>
To: Jeremy Orlow <jorlow@chromium.org>
Cc: Olli@pettay.fi, public-webapps@w3.org
That would be a good solution in my opinion, although if you wanted to check
if the event was dispatched by the current document or another, I believe
you could use the source property that the spec currently contains, and just
do something like:

ev.source == window ?

That seems to work as expected in Safari 4.0.4 (I assume production builds
of Chrome as well).

-J

On Fri, Jan 29, 2010 at 10:36 AM, Jeremy Orlow <jorlow@chromium.org> wrote:

> We could change it to fire in all windows and have a boolean that says
> whether you fired it.  Maybe that's the best solution?
>
>
> On Fri, Jan 29, 2010 at 10:33 AM, Jared Morse <jarcoal@gmail.com> wrote:
>
>> Hi Jeremy, your patch (https://bugs.webkit.org/show_bug.cgi?id=30546) is
>> actually what brought this to my attention.
>>
>> I cannot think of an example where iframe's would not be sufficient as a
>> work-around, however it could potentially be inconvenient to use them,
>> especially when your app may be open in several tabs.  Each other tab would
>> get two events triggered, one for the primary document and one for the
>> iframe inside of it.  While this isn't the end of the world, clearly you
>> would need to always check the source of the iframe event, to make sure it
>> came from it's parent, and not another tab.
>>
>> Between this and Olli's prototype suggestion, it is clear there are
>> definitely ways around this issue should a developer face it.  However, I do
>> think the advantage of having your "glue" code written for you would be of
>> great benefit to developers.
>>
>> -J
>>
>>
>> On Thu, Jan 28, 2010 at 3:06 PM, Jeremy Orlow <jorlow@chromium.org>wrote:
>>
>>> On Thu, Jan 28, 2010 at 2:22 PM, Jared Morse <jarcoal@gmail.com> wrote:
>>>
>>>> Perhaps I am mistaken, but I believe you would still have to go around
>>>> and add that trigger to all the places the value is changed from.
>>>>
>>>
>>> That is true.
>>>
>>> Can you give some clear examples of when having local storage events
>>> being fired in your frame would be useful?  Bonus points if they're
>>> something that can't be handled by simply creating an iframe within your doc
>>> and using it to monitor events (which is the obvious work-around).
>>>
>>> J
>>>
>>>
>>>> On Thu, Jan 28, 2010 at 2:06 PM, Olli Pettay <Olli.Pettay@helsinki.fi>wrote:
>>>>
>>>>> On 1/28/10 11:57 PM, Jared Morse wrote:
>>>>>
>>>>>> Even though it occurs on the same document, doesn't mean loosely
>>>>>> coupled
>>>>>> code can't benefit from it.
>>>>>>
>>>>>> Imagine if each time you added a feature to a web app that depended on
>>>>>> knowing a current value from the storage, you'd have to go around to
>>>>>> all
>>>>>> the places that value is changed and add some code to alert your new
>>>>>> code.  If storage events triggered on the same document, all you would
>>>>>> have to do is set a listener.
>>>>>>
>>>>>
>>>>> If you really need this behavior, you can always dispatch your own
>>>>> event
>>>>> to the window when you change the data.
>>>>>
>>>>>
>>>>> -Olli
>>>>>
>>>>>
>>>>>
>>>>>> -J
>>>>>>
>>>>>> On Thu, Jan 28, 2010 at 1:41 PM, Olli Pettay <Olli.Pettay@helsinki.fi
>>>>>> <mailto:Olli.Pettay@helsinki.fi>> wrote:
>>>>>>
>>>>>>    On 1/28/10 9:34 PM, Jared Morse wrote:
>>>>>>
>>>>>>        Hi, I have a concern about the web storage event spec
>>>>>>        (http://dev.w3.org/html5/webstorage/).
>>>>>>
>>>>>>        The spec states:
>>>>>>        "When the setItem(), removeItem(), and clear()  methods are
>>>>>>        called on a
>>>>>>        Storage object x that is associated with a local storage area,
>>>>>>        if the
>>>>>>        methods did something, then in every HTMLDocument object whose
>>>>>>        Window
>>>>>>        object's localStorage attribute's Storage object is associated
>>>>>>        with the
>>>>>>        same storage area, other than x, a storage event must be
>>>>>> fired..."
>>>>>>
>>>>>>        My concern lies with the "other than x" part.  Unless I'm
>>>>>> missing
>>>>>>        something, these events would be even more useful if they also
>>>>>>        fired in
>>>>>>        the HTMLDocument that initially made the storage call.
>>>>>>
>>>>>>
>>>>>>    The page which is changing storage object knows already that the
>>>>>>    storage object is being changed. Why would it need explicit
>>>>>>    notification (event) about that?
>>>>>>
>>>>>>
>>>>>>    -Olli
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>        Thanks for your time.
>>>>>>
>>>>>>        -Jared
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
Received on Friday, 29 January 2010 19:14:01 GMT

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