W3C home > Mailing lists > Public > public-bpwg@w3.org > March 2008

ACTION-713 Review some AJAX resources

From: Sean Owen <srowen@google.com>
Date: Thu, 13 Mar 2008 16:28:36 -0400
Message-ID: <e920a71c0803131328jad48150lef53087ef72e364a@mail.gmail.com>
To: "Mobile Web Best Practices Working Group WG" <public-bpwg@w3.org>

Here is my condensation of points that seem to have some possible
mobile-specific connection -- maybe just by seeming even more
important on mobile. I came away with six possible BPs to consider
including, with proper attribution to source of course.


1. Separate JavaScript into external files; no JavaScript in markup
(maybe has performance/caching benefits)
2. Content should be basically usable without JavaScript (more likely
to encounter devices with limited or no script in mobile)


These are largely *accessibility* concerns, and I am not clear any of
them overlap enough with *mobile-specific* concerns to include, but,
here is my summary anyway

- Dynamic changes to page content need to be relayed to a screen reader.
  - ECMAScript focus method can be used to place focus to the part of
the page that has changed
  - Can use a tabindex='-1' hack to make more elements focusable,
assisting the above
  - ... some problem with readers and tables embedded in forms that I
didn't understand -- there is some practice here though!
- (Not explicitly mentioned, but seems to be implied) Always set the
"title" attribute wherever you can -- used by readers


3. Offer to disable automatic updates of information (e.g. stock
price, temperature) (reduces data usage)
4. Provide "notification" of changes (not sure exactly what this
means). Helps accessibility, but also helps the UA zoom/pan to the
update area (small browser window on mobile may not even show the area
that was updated, when it needs attention)
5. Don't shift focus when an update occurs (input is hard, usually a
special mode, on mobile -- don't shift out of it capriciously)
6. Update elements with new content instead of adding elements. For
example add an empty <div> and fill it later. (Hmm, does this reduce
rendering overhead, and thus processing power usage / battery


(Actually just about a book of best practices -- anyone want to get a copy?)
Received on Thursday, 13 March 2008 20:34:59 UTC

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