W3C home > Mailing lists > Public > www-dom@w3.org > April to June 2009

Re: Mutation events - slowness examples

From: David Bolter <david.bolter@gmail.com>
Date: Thu, 25 Jun 2009 13:43:29 -0400
Message-ID: <4A43B741.5050206@gmail.com>
To: Sergey Ilinsky <castonet@yahoo.co.uk>
CC: Maciej Stachowiak <mjs@apple.com>, Jonas Sicking <jonas@sicking.cc>, François REMY <fremycompany_pub@yahoo.fr>, "Michael A. Puls II" <shadow2531@gmail.com>, Sean Hogan <shogun70@westnet.com.au>, www-dom@w3.org
On 6/25/09 5:04 AM, Sergey Ilinsky wrote:
>> In conclusion, I think the data presented shows the performance
>> characteristics of mutation events to be unacceptable in current browsers
>> to endorse them as a common technique.
> 1) Unacceptable performance characteristics and unreasonable UI slowdown caused
> There are many ways to slow down a browser and hence end user experience besides using Mutation Events (including those not requiring scripting at all, but solely using CSS, SVG etc)
> Developers do use these and many other ways, also because popular JS libraries promote those ways - both in practices and inefficient implementations
> 2) Endorsing Mutation Events as a common technique
> I think this will hardly happen. First because there is very tiny amount of developers who know Mutation Events exist, and a lesser amount of those who understand what they could/should be used for. Second, because there are simply no sensefull use cases (on the web) for them (see an earlier attempt to define on them)

Hi Sergey,

Apologies if this is old news but I'm not sure what earlier attempt you 
are referring to.

One potential use case is coming via WAI-ARIA:

I'm not a big proponent of this; just noting it as a use case. The idea 
is that modifications to the aria-activedescendant attribute 
(DOMAttrModified) are expected to be handled by the web developer, and 
the visual appearance of focus to be restyled. Related exploration I did 
for the W3C is here: 

I used browser sniffing instead of feature detection so that it self 
documented to my audience the state of browser support.

Received on Thursday, 25 June 2009 17:44:15 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 22:36:55 UTC