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Response to "Techniques for WCAG 2.0"

From: Joe Clark <joeclark@joeclark.org>
Date: Tue, 23 May 2006 17:14:19 +0000 (UTC)
To: public-comments-wcag20@w3.org
Message-ID: <Pine.LNX.4.60.0605231711400.14640@aristotle.multipattern.com>



Instant-messaging applications are not Web content

      An instant-messaging application uses two simple glyphs to indicate
      a person's instant messaging status.

    An instant-messaging application is not Web content. (Yes, I know,
    it's possible to use the Web as a front end for instant messaging, as
    with Google Chat and Meebo. Those are not applications.)

Text equivalents

    alt=" " is officially permitted alongside the actually correct alt="".

Incorrect CSS or usage

    The Techniques document gives incorrect CSS in places, or simply gives
    unrealistic examples that don't match the practices of
    standards-compliant developers.

/* Rules for bidi */
HEBREW, HE-QUO {direction: rtl; unicode-bidi: embed}
ENGLISH {direction: ltr; unicode-bidi: embed}
/* Rules for presentation */
HEBREW, ENGLISH, PAR {display: block}
EMPH  {font-weight: bold}

        Each of those class names must begin with a dot (e.g., .HEBREW),
        and all-lower-case is preferred, as XML documents have
        [3]case-sensitive CSS parsing.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  <html xmlns="<url>http://www.w3.org/1999/xhtml">http://www.w3.org/1999/xhtml</
  <title>A study of population dynamics</title>
  <body bgcolor="white">
  <p> ... document body...</p>

        body bgcolor="" is an incorrect usage; that's what we have CSS
        for. (Same for body color="" later.) Note that the DOCTYPE URL is


          1. Examine the code of the Web unit.
          2. Check to see if a foreground color is specified.
          3. Check to see if a background color is specified.

        Colours may have been specified in preceding selectors. The C in
        "CSS" does stand for "cascading," after all. As written, this
        technique authorizes pedants to write in and complain that not
        every single element has foreground and background colours
        explicitly stated. They don't have to be.

Trivial examples

      One of the most common examples of using inconsistent labels for
      components with the same function is to use a button that says
      "search" in one page and to use a button that says "find" on
      another page when they both serve the identical function.

    And the words have identical meaning.

Failure Example 4:

      An E-commerce application uses a printer icon that allows the user
      to print receipts and invoices. In one part of the application, the
      printer icon is labeled "Print receipt" and is used to print
      receipts, while in another part it is labeled "Print invoice" and
      is used to print invoices. The labeling is consistent ("Print x"),
      but the labels are different to reflect the different functions of
      the icons. Therefore, this example does not fail the success

    So why is it in there?

Testing in browsers

      The blink value of the text-decoration property is not supported by
      Internet Explorer.

    For Windows or Mac?

      It is supported in Netscape/Mozilla family browsers. Not tested in
      others (e.g., Safari, Opera).

    And why wasn't it tested in those "others"?

Blinking (but not flashing)


      CSS defines the blink value for the text-decoration property. When
      used, it causes any text in elements with this property to blink at
      a predetermined rate. This cannot be interrupted by the user, nor
      can it be disabled as a user-agent preference.
        User stylesheets would seem to be useless in this regard, as they
        do not permit the rewriting of selectors. However, User Agent
        Accessibility Guidelines [4]Checkpoint 3.3 requires the ability to
        toggle blinking text. This appears to be a user-agent problem, in
        whole or in part.

      On a page with moving or scrolling content,
          1. Check that a mechanism is provided in the Web unit or user
             agent to pause moving or scrolling content.
          2. Use the pause mechanism to pause the moving or scrolling
          3. Check that the moving or scrolling has stopped and does not
             restart by itself.
          4. Check that a mechanism is provided in the Web unit or user
             agent to restart the paused content.
          5. Use the restart mechanism provided to restart the moving
          6. Check that the movement or scrolling has resumed from the
             point where it was stopped.

        But the Understanding document uses an example of a stock ticker:

      A stock ticker has "pause" and "restart" buttons. Pausing the
      ticker causes it to pause on the current stock. Restarting causes
      the ticker to jump ahead to the current stock. Stocks that were
      updated during the pause will not be displayed.
        So which is it: Once you resume you have to start from where you
        paused, or can you skip what you missed?



      Examples of text streams that are not captions include... subtitles
      that do not include important sounds
        No "subtitles" are "captions." By implication, this technique
        permits subtitling into a foreign language as long as non-speech
        information is included.


          1. View the material with captioning turned on.
          2. Check that all dialog is accompanied by a caption.
          3. Check that all important sounds are captioned.

        And how does a deaf person do this?

Keyboard access



     1. Using a keyboard, navigate through the content.
     2. Check to see that the keyboard focus is not "trapped" and it is
        possible to move keyboard focus out of the plug-in content without
        closing the user agent or restarting the system.

    What if this depends on the user agent, as it so often does? What if
    nothing the author can do will ever permit the user to escape from the
    trapping content? (This was a real example with accessible Flash.)

Popup windows


      Failure due to opening new windows when the user does not expect
      them. New windows take the focus away from what the user is reading
      or doing. This is fine when the user has interacted with a piece of
      user interface and expects to get a new window, such as an options
      dialogue. The failure comes when pop-ups appear unexpectedly.
        Actually, WCAG 2 [5]bans all popup windows without explicit alert
        beforehand (though at Level 3).

      A user clicks on a link, and a new window appears. The original
      link has no associated text saying that it will open a new window.
      [...] Check if elements that open new windows have associated text
      saying that will happen. The text can be displayed in the link, or
      available through a hidden association such as an HTML title
        target="_blank" is programmatically determinable and it is up to
        the user agent to warn the user. JavaScript is another story and
        should be addressed by the Techniques.

      A user clicks on the body of a page and a new window appears. No
      indication that the area that was clicked has functionality is
        If that area were marked up as a or indeed as area, such warning
        is programmatically determinable and it is up to the user agent to
        warn the user.

Linguistics & typography


      The objective of this technique is to show how using a non-text
      mark to convey information can make content difficult to
      comprehend. A non-text mark may be non-text content such as an
      image, or a font glyph which is not text nor an image of text.
        Font glyphs are text. This whole section is nonsense.

      The objective of this technique is to describe how using blank
      characters, such as space, tab, line break, or carriage return, to
      format individual words visually can be a failure to present
      meaningful sequences properly. Blank characters have no appearance
      when rendered visually
        Yes, they do. They're blank!

    You are here: [6]joeclark.org -> [7]Captioning and media access ->
    [8]Web accessibility -> [9]WCAG -> Response to `Techniques for WCAG

    Updated 2006.05.23


    1. LYNXIMGMAP:http://joeclark.org/access/webaccess/WCAG/response1_Techniques-WCAG2.html#joeclark_angie_02IX_Map
    2. http://www.w3.org/TR/WCAG20-TECHS/
    3. http://www.w3.org/TR/CSS21/selector.html#q1
    4. http://www.w3.org/TR/UAAG10-TECHS/guidelines.html#tech-on-off-blinking-text
    5. http://joeclark.org/access/webaccess/WCAG/WX#%23context-changedef
    6. http://joeclark.org/
    7. http://joeclark.org/access/
    8. http://joeclark.org/access/webaccess/
    9. http://joeclark.org/access/webaccess/WCAG/
Received on Tuesday, 23 May 2006 17:14:47 UTC

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