[whatwg] Feedback on UndoManager spec

[Aryeh Gregor]

On Tue, Nov 8, 2011 at 11:55 AM, Ryosuke Niwa <rniwa at webkit.org> wrote:
> On Tue, Nov 8, 2011 at 6:12 AM, Aryeh Gregor <ayg at aryeh.name> wrote:
>>
>> > Yeah, it'll be nice if we could define the behavior precisely but then
>> > again, there's nothing that prevents authors from modifying DOM in any
>> > arbitrary way.
>>
>> Right, but at least then it will either work in all browsers or break
>> in all browsers.
>
> I don't really follow your logic here.

If the behavior is not defined precisely, different browsers will
behave differently.  This means a page might work in one browser, but
not in another.  So authors will write a page, test, find that it
breaks, and work around the problem so that their tests work in all
browsers they care about.  Then it will still break in other browsers.
 Or else authors have to fix the page so it works in one browser, then
write entirely different fixes for another browser.

Having browsers behave differently is always bad.  Behavior should be
standardized so they behave the same.  Even if the behavior is bad and
it's not what authors want, authors can always work around it to get
what they want, as long as it's the same in all browsers.  So the most
important thing is all browsers have the same behavior, and the second
most important thing is that the behavior is actually desirable.

> Attributes are easy because it's just a string, and we can always restore
> that. CharacterData is tricky since I don't want force UAs to store the
> entire old data.

See other thread for my brief investigations on how UAs seem to do
this in practice (they don't seem to store the old data, just any
deleted parts).