This document describes techniques that may be used by software programs
in evaluating the conformance of HTML documents to
The Web Content Accessibility
Guidelines 1.0. It also describes techniques that may be used in software
programs for modifying HTML documents so that they conform to these
guidelines.
This is a W3C Working Draft for review by the Evaluation and Repair
Tools Working Group and other invited parties. It has not been reviewed by the
WAI Interest Group. It is a draft document and may be updated, replaced, or
obsoleted by other documents at any time. It is inappropriate to use W3C
Working Drafts as reference material or to cite them as other than "work in
progress". A list of current W3C Recommendations and other technical documents
can be found at http://www.w3.org/TR.
Please send comments on this document to
w3c-wai-er-ig@w3.org.
- Clean up all of the @@'s (editor questions and comments).
- Check for consistent language usage.
- Link to WCAG, AU and UA Techniques and EO Curriculum where
appropriate.
- Use WCAG notes or rationale as example language where possible,
unless we have something clearer.
- Inherit all of the reference info between checkpoints from WCAG
(e.g., at the end of Checkpoint 10.1, "refer also to Checkpoint 12.4").
- Determine if we want to use "author" or "user." Then check for
consistent usage.
- Determine if we want to use "document" or "page." Then check for
consistent usage.
- Ensure that "Web" is capitalized consistently.
- Ensure that links to test and discussion files have unique link
text.
- Resolve
open
issues.
The Web Accessibility Initiative (WAI) has produced a foundation
document, The WAI Web Content
Accessibility Guidelines (WCAG 1.0), that describes what must be done to
make a Web page accessible to all. Tools are needed to help authors determine
if a web site is accessible to everyone and to help repair it if it is not.
This document builds on the WCAG 1.0 foundation by outlining techniques
that evaluation and repair tools may use to uncover accessibility problems and
possibly repair them. These techniques may be used by those who create web
authoring tools or by anyone interested in creating accessible Web
documents.
It is important that people with disabilities are included in the
"anyone interested in creating accessible Web content." Creating accessible Web
content is as important as accessing Web content. Therefore, evaluation and
repair tools themselves need to be accessible to people with disabilities.
However, this document does not describe how to make the user interface
accessible. Please refer to the User
Agent Accessibility Guidelines for information on making the user interface
accessible.
Many people using evaluation and repair tools may be new to the Web and
will not be familiar with the various markup languages that are used. Many
others will not know about Web accessibility. Tools should be intuitive and
easy to use and available at a minimal cost. Tools should not generate
excessive warnings or false positive accessibility errors.
Some of the web-content accessibility checkpoints cannot be checked
successfully by software algorithms alone. There will still be a dependence on
the user's ability to exercise human judgment to determine conformance to the
guidelines. It is imperative that any tool have features that assist in
reminding, without nagging; in helping, without demeaning; in suggesting,
without demanding. We hope that the techniques in this document, implemented in
software programs, will gently guide authors along the path to more accessible
documents.
This document is based on The WAI Web Content Accessibility
Guidelines. It lists each guideline and checkpoint in in that document.
Under each checkpoint it lists one or more techniques for evaluating and, in
some cases, repair. Each technique comprises the following
subsections:
- Discussion status
- This section lists open issues and questions about a particular
technique.
- Evaluation:
- The algorithmic and heuristic tests that will be applied. consisting
of
- Elements - the elements to which this test
applies, e.g.
<IMG>
etc. If it only applies to an element of a particular
type, this is noted (e.g. <INPUT
TYPE="image"
>
- Requirements - the conditions which will be
tested for by means of algorithms and heuristics.
Note: in a few cases, the warning is always presented.
- Suggested message:
- Messages displayed to the author if the element is found and the
requirement is not satisfied.
- Suggested repair:
- Actions that may be required to repair the accessibility
problem.
- Test files:
- Used to test evaluation tools to see if they find the accessibility
problem.
- Discussion files:
- Discussion and comments on the technique.
Note. This document specifies only the function of
evaluation and repair tools. Nothing in this document should be taken to imply
a particular user interface.
Guideline 1.
Provide equivalent alternatives to auditory and visual content.
- Checkpoint 1.1 - Provide a text
equivalent for every non-text element
-
- Checkpoint 1.2 - Provide
redundant text links for each active region of a server-side image map
-
- Checkpoint 1.3 - Until user
agents can automatically read aloud the text equivalent of a visual track,
provide an auditory description of the important information of the visual
track of a multimedia presentation
-
- Checkpoint 1.4 - For any
time-based multimedia presentation (e.g., a movie or animation), synchronize
equivalent alternatives (e.g., captions or auditory descriptions of the visual
track) with the presentation
-
- Checkpoint 1.5 - Until user agents render
text equivalents for client-side image map links, provide redundant text links
for each active region of a client-side image map
-
Technique 1.1.1 [priority 1] Check
IMG
elements for valid "alt
" attribute
- Element:
<IMG>
- Requirement: Valid "
alt
" attribute.
Valid "alt
" attribute:
Note: We're awaiting word from GL on null and blank alt-text. See
discussion at
http://lists.w3.org/Archives/Public/w3c-wai-er-ig/1999Jun/0050.html
especially part about null or blank alt-text for links.
- "
alt
" attribute must exist
- Not allowed - NULL "
alt
" value (alt=""
)
- Allowed - "
alt
" value of 1 or more spaces ("alt="
"
") but only if
image is not within an "A
element
"
- Suspicious - "
alt
" attribute value could be file size (ends with
"bytes")
- Suspicious - "
alt
" attribute value ends with image file suffix.
- Suspicious - "
alt
" attribute value is placeholder text.
- Suspicious - "
alt
" attribute value is longer than 150 characters.
Suggest that a description file be created.
- Missing text equivalent: Missing text equivalent for image.
- Suspicious "
alt
" attribute: Suspicious text equivalent for image:
[current "alt
" text] - [could be file size | could be file name | could be
placeholder text | text equivalent should be short, perhaps this could be a
"longdesc
"].
- Invalid "
alt
" attribute: Invalid text equivalent for image: [text
equivalents can not be empty].
- Prompt the user for a text equivalent for the image.
- If the document contains another instance of the image and that image
contains an "
alt
" attribute, suggest that "alt
" attribute value.
- If the image is assumed to be a bullet,
suggested text should be "bullet".
- If the image is assumed to be a horizontal
rule, suggested text should be "horizontal rule".
- Other suggestions
by Daniel Dardailler
- Suggestions
by Michael Vorburger
- After user has entered an
"alt"
attribute for the image, check the
site for other instances of the image. If the site contains other images that
are the same and they do not have a text equivalent, suggest that all same
images without an "alt
" attribute use the new "alt
" attribute
value.
Test Files and Discussion Files:
Technique 1.1.2 [priority 1]
Verify that valid IMG
element descriptions ("longdesc"
attribute or d-link)
are provided where necessary.
- Element:
<IMG>
- Requirements:
- Valid "
longdesc
" attribute or a d-link required if describing the
image will add information not given in the text of the page. The amount of
information in the image and the context in which it is used will determine how
detailed the description should be. Note: d-link now deprecated.
- Cases where a description is not required:
Valid "longdesc
" attribute:
- If describing the image will add information not given in the text of
the page, you need to provide a description of the image. The amount of
information in the image and the context in which it is used will determine how
detailed the description should be.
- Ask user if the image presents information that is not included in
the page or in the text equivalent for the image. Allow the user to create or
associate a description.
- with the "
longdesc
" attribute on an IMG
element
- via a D-link
- If another document on the same site uses the same image and has a
"
longdesc
", suggest that "longdesc
" file.
Technique 1.1.3 [priority 1] Check
INPUT
elements of type="image"
for valid "alt
" attribute
- Element:
<INPUT type="image">
- Requirement: Valid "
alt
" attribute.
Valid "alt
" attribute:
- "
alt
" attribute must exist
- Not valid - NULL "
alt
" value (alt=""
)
- Not valid - "
alt
" value of 1 or more spaces (alt="
"
)
- Suspicious - "
alt
" attribute value could be file size (ends with
"bytes")
- Suspicious - "
alt
" attribute value ends with image file suffix.
- Suspicious - "
alt
" attribute value is placeholder text.
- Missing text equivalent: Missing text equivalent for this
button.
- Suspicious text equivalent: Suspicious text equivalent for button:
[current "
alt
" attribute] - [could be file size | could be file name |
could be placeholder text].
- Invalid text equivalent: Invalid text equivalent for button: [
"
alt
" attribute can not be empty | text equivalent can not contain only
'spaces'].
- Prompt the user for text equivalent.
- If another document on the same site has an INPUT element with the
same TYPE value, suggest that type value.
Technique 1.1.4 [priority 1]
Check APPLET
elements for valid HTML equivalent
- Element:
<APPLET>
- Requirements:
- Valid "
alt
" attribute OR
- accessible HTML within
APPLET
element
Valid "alt"
attribute values:
- Not allowed - NULL "
alt
" attribute value (alt=""
)
- Not allowed - "
alt
" attribute value of 1 or more spaces (alt="
"
)
- Suspicious - "
alt
" attribute value could be file size (ends with
"bytes")
- Suspicious - "
alt
" attribute value ends with image file suffix.
- Suspicious - "
alt
" attribute value is placeholder alt-text text.
- Suspicious - "
alt
" attribute ends with applet executable suffix.
- Allowed - no "
alt
" attribute if text is provided within the
content of the APPLET
element.
- Missing text equivalent: Applet must have valid a valid "
alt
"
attribute or accessible HTML content."
- Suspicious text equivalent: Suspicious text equivalent for applet:
[current "
alt
" attribute value] - [could be file size | could be image file
name | could be placeholder text | could be applet executable name].
- Invalid text equivalent: Invalid "
alt
" attribute for applet -
[text equivalent can not be empty | text equivalent can not be all
'spaces'].
- Prompt the user for text equivalent.
- If the same applet is used on the same site and has an "
alt
"
attribute, suggest that "alt
" attribute value.
Technique 1.1.6 [priority 1]
Check OBJECT
elements of type="<image MIME types>" for valid text
equivalents and descriptions (where necessary)
@@this just says text equivalents. len's additions are non-text. where
is non-text covered if not here?
- Element:
<OBJECT>
- Requirement: Between
OBJECT
start element and OBJECT
end element
must be a valid alternative representation element.
Valid alternative representation element:
- Missing alternative representation: Missing alternative
representation for this object.
- Suspicious alternative representation: Suspicious alternative
representation for this object: [current alternative representation] - [could
be placeholder text]
- @@likewise, might be "missing text equivalent"
- Prompt user for new alternative representation.
- If the site contains a document that contains the same object and
that object contains a valid alternative representation, suggest that
alternative representation.
Link to test files
for this technique.
@@LRK: divided 1.1.7 into two cases: "linked" and "embedded" audio
since the tests are different.(is "linked" proper terminology for object?)
Technique 1.1.7 [priority 1] Verify
that text equivalents are provided for linked audio files where
necessary
- Elements:
<A href=soundFile>
- Requirement: Audio file must be described within the document or
document must contain a link to a text equivalent file.
- Audio files require a text equivalent. Is there an associated text
equivalent for this audio file: [audio file name]?
- Prompt user for text transcript of audio file.
Link to test files
for this technique.
Technique 1.1.8 [priority 1]
Verify that text equivalents are provided for embedded audio files
where necessary
Evaluation:
- Elements:
<OBJECT type=
Audio or Video MIME
TYPE
>
- Requirement: Audio file must be described within the document or
document must contain a link to a text equivalent file.
- Audio and video files require a text equivalent. Is there an
associated text equivalent for this audio/video file: [audio/video file
name]?
- Prompt user for text transcript of audio/video file and embed it
between start and end tag.
Technique 1.1.9 [priority 1] Check
FRAME
elements for valid "longdesc
" attribute
- Element:
<FRAME>
- Requirement: Valid "
longdesc
" attribute (refer to checkpoint 12.1 for
information about titling frames).
- If a
FRAMESET
has three or more frames and at least one of the frames
does not have a "longdesc
" attribute, ask the user if the relationships between
frames are not apparent in the titles for each frame.
Valid "longdesc
" attribute:
- Must not be NULL
- Must be a valid URI
- The file pointed to by the URI must be accessible HTML @@LRK::
Added
- Missing "
longdesc
": Missing description for this frame.
- Invalid "
longdesc
" URI: Invalid 'long description' file name for this
frameset: [current "longdesc
" URI] - [can not be empty].
- If the relationships between frames are not obvious then ask that
they provide a description of the relationships. Allow the user to create a
"
longdesc
" file or associate an existing "longdesc
" file. It is suggested that
each FRAME
in the reference the same "longdesc
" as the description of the
relationships should be available from each FRAME
.
Technique 1.1.10 [priority 1] Check AREA
elements for valid "alt
" attribute
- Element:
<AREA>
- Requirement: Elements must have a valid "
alt
" attribute.
Valid "alt
" attribute:
- Not allowed - NULL "
alt
" value (alt=""
)
- Suspicious - "
alt
" attribute value is placeholder text.
- @@is this complete?
- Missing text equivalent: Missing text equivalent for this image map
area.
- Suspicious "
alt
": Suspicious "alt
" attribute for this image
map area: [current alt text].
Prompt user for "alt
" text for the AREA
element.
Technique 1.1.11 [priority 1] Check
SCRIPT
elements for valid equivalents where necessary
- Element:
<SCRIPT>
- Requirements:
NOSCRIPT
section must follow the SCRIPT
end element AND
NOSCRIPT
section must contain Accessible HTML
NOSCRIPT
section must not contain placeholder
text
Suggested message:
- Language for missing
NOSCRIPT
: Missing NOSCRIPT
element for this
SCRIPT
element.
- If contained HTML not accessible:
NOSCRIPT
section contains
inaccessible HTML: [description of problems].
- Insert
NOSCRIPT
section
- Allow user to insert text or link to text equivalent file that
describes the
SCRIPT
@@No information at this time.
Technique 1.1.13 [priority 1] Verify that
valid text equivalents are provided for PRE
and XMP
elements used to
create ASCII art.
- Elements:
PRE
and XMP
- Requirement: ASCII art has an associated text equivalent.
@@The algorithm A-Prompt has been using for ASCII art detection is:
There must be 5 or more lines of text and there must be 5 or more same
characters in a sequence. This works quite well but detects things such as code
samples (don't require text equiv.) and guitar tabulature (do require text
equiv.). I have a list of ASCII art pages that we have tried this on if you
would like to see results.
ASCII Art
Discussion Page
- Character based artwork (ASCII art) requires a textual
description.
- Ask user for a description of the ASCII art or allow them to add a
link to a text equivalent file.
Technique 1.2.1 [priority 1]
Verify that a server-side image map has associated text links.
@@LRK: Issue: Text links only priority 3 if the same image also has a
client side map (images can have both). This is an issue I raised with
WCAG.
- Element:
<IMG ISMAP>
- Requirement: text link for each active area of the image map
- Server-side image maps should have associated text links in the
document.
- Prompt the user for associated text links OR
- help the user convert the server-side image map to a client-side
image map and provide text-equivalents for each link in the client-side image
map.
- If possible, check the text links against the links contained on the
server-side image map by @@LRK added
- asking user to upload the server side definition file if it's a
standard format or
- pinging the image map with random coordinates and seeing if all
returned pages correspond to the links.
Technique 1.3.1 [priority
1] Verify that multimedia have audio descriptions.
- Elements:
- <
any_tag
any_attribute=multimedia_uri
>,
OBJECT
type=
any_multimedia_type
- @@LRK: is this correct and complete?
- Requirement: Multimedia presentations should have an associated audio
description.
- @@CR - Does this mean that the repair is to create an audio file
(record the repair persons voice)?
- Display the multimedia file and allow the user to create an audio
description of the important information.
- Allow the user to add a link to an existing audio description
file.
Checkpoint 1.4 - For any
time-based multimedia presentation (e.g., a movie or animation), synchronize
equivalent alternatives (e.g., captions or auditory descriptions of the visual
track) with the presentation
Technique 1.4.1 [priority 1]
Verify that multimedia have synchronized equivalents.
@@CR: The key word in this guideline seems to be 'synchronize'. How do
we synchronize any equivalent alternatives? Can this be done in the HTML
code?
- Elements:
- <
any_tag
any_attribute=multimedia_uri
>,
OBJECT
type=
any_multimedia_type
- @@LRK: is this correct and complete? @@Any multimedia
object will generate a user notification
- Requirement: Multimedia presentations should have a synchronized
equivalents.
- For any time-based multimedia presentation (e.g., a movie or
animation), synchronize equivalent alternatives (??what's the right phrase from
WCAG to use here?@@)
- Give user option to edit option with editor of their choice (e.g. the
default editor on their system) @@LRK
@@LRK Omit this section? Seems to duplicate 1.4.a
- SMIL Elements:
- Requirement: SMIL files should have the
system-captions
flag for at least one
text stream and one auditory stream.
Checkpoint 1.5 - Until user agents render
text equivalents for client-side image map links, provide redundant text links
for each active region of a client-side image map
Technique 1.5.1 [priority 3]
Verify that text links are provided for client-side image maps.
- Element:
<IMG usemap>
- Requirement: Document must contain text links for each active area of
the image map.
- Associated text links may be found by searching the document for
anchors with
href
attribute values that correspond to the AREA
elements
in the given usemap
.
- Client-side image maps should have associated text links.
- Allow the user to create associated text links for each active area
in the image map.
Guideline 2. Don't rely on color alone.
- Checkpoint 2.1 - Ensure that all
information conveyed with color is also available without color, for example
from context or markup
- Checkpoint 2.2 - Ensure that foreground
and background color combinations provide sufficient contrast when viewed by
someone having color deficits or when viewed on a black and white screen
Checkpoint 2.1 - Ensure that all
information conveyed with color is also available without color, for example
from context or markup
Technique 2.1.1 [priority 1] Verify that
information conveyed with color is available without color
- Elements:
IMG |
APPLET |
OBJECT |
SCRIPT |
INPUT |
as well as the HTML
elements and attributes listed in the next technique (2.2.1).
- Ensure that information is not conveyed through color alone. For
example, when asking for input from users, do not write "Please select an item
from those listed in green." Instead, ensure that information is available
through other style effects (e.g., a font effect) and through context (e.g,.
comprehensive text links).
- Display a user notification if any of the color-possible elements are
in the document.
Checkpoint 2.2 - Ensure that foreground
and background color combinations provide sufficient contrast when viewed by
someone having color deficits or when viewed on a black and white screen
Technique 2.2.1 [priority 3] Test
the color attributes of the following elements for visibility:
- Elements:
<BODY bgcolor | text | alink | link | vlink | background
=
anything
> OR
<TABLE bordercolor | bgcolor
=
anything
> OR
<TD | TH bgcolor
=
anything
> OR
<HR color =
anything
>
OR
<
any_element
style="
any_color_specification
">
<STYLE> "any_color_specification"...
</STYLE>
- Where any_color_specification is defined as any CSS
specification which contains:
color | background-color | background-image |
background
- Requirement: Determine color visibility.@@needs work?
Ideally, images and multimedia object should also be tested for color
visibility but algorithms are beyond the scope of this specification @@LRK
Color visibility can be determined according to the following
algorithm:
(This is a suggested algorithm that is still open to
change.)
Two colors provide good color visibility if the brightness difference
and the color difference between the two colors are greater than a set
range.
Color brightness is determined by the following formula:
((Red value
X 299) + (Green value X 587) + (Blue value X 114)) / 1000
Note: This
algorithm is taken from a formula for converting RGB values to YIQ values. This
brightness value gives a perceived brightness for a color.
Color difference is determined by the following formula:
(maximum
(Red value 1, Red value 2) - minimum (Red value 1, Red value 2)) + (maximum
(Green value 1, Green value 2) - minimum (Green value 1, Green value 2)) +
(maximum (Blue value 1, Blue value 2) - minimum (Blue value 1, Blue value
2))
The rage for color brightness difference is 125. The range for color
difference is 500.
- Poor visibility between text and background colors.
- Allow the user to change the poor color combinations.
- Store any good color combinations entered by the user and use them as
default prompts in the future.
Guideline 3. Use markup and style
sheets and do so properly
- Checkpoint 3.1 - When an appropriate
markup language exists, use markup rather than images to convey
information
-
- Checkpoint 3.2 - Create documents that
validate to published formal grammars
-
- Checkpoint 3.3 - Use style sheets to
control layout and presentation
-
- Checkpoint 3.4 - Use relative rather
than absolute units in markup language attribute values and style sheet
property values
-
- Checkpoint 3.5 - Use header elements
to convey document structure and use them according to specification
-
- Checkpoint 3.6 - Mark up lists and list
items properly
-
- Checkpoint 3.7 - Mark up quotations. Do not use
quotation markup for formatting effects such as indentation
-
Checkpoint 3.1 - When an appropriate markup
language exists, use markup rather than images to convey information
Technique 3.1.1 [priority 2] Verify
that elements do not need to be converted to an appropriate markup
language.
- Elements:
PRE | IMG | OBJECT | APPLET
- When an appropriate markup language exists, use markup rather than
images to convey information. For example, use MathML to mark up mathematical
equations, and style sheets to format text and control layout
-
- Display a user notification if any of these possible conversion
elements are in the document.
- Help authors convert decorative ASCII art in PRE elements to SVG or
an image format. @@CR - Is this necessary? We already prompt for a text
description of ASCII art.
- Help authors convert ASCII art representing tables of data in PRE
elements to TABLE elements.
- Help authors convert images (
IMG
or OBJECT
) used to format text
to XHTML/XML with style sheets.
- Help authors convert images (
IMG
or OBJECT
) used to format
mathematical equations to MathML.
Checkpoint 3.2 - Create documents that validate
to published formal grammars
Technique 3.2.1 [priority 2] Check
document for public text identifier
- @@reference BizTalk and OASIS catalogs?
- Element: none (i.e. applies to all documents)
- Requirements:
- If no <!DOCTYPE ...> at all: Missing language identifier for
this document.
- If document type is defined in HTML element: "Document type should be
in the document type definition. It's use in the HTML element is
deprecated @@ added by LRK.
- If the document type is in the HTML element: move to the <!DOCTYPE
...> declaration.
- If no valid document type at all: Prompt the user for a public text
identifier, preferably by offering a menu of choices and explanations @@LRK
added menu
Checkpoint 3.3 - Use style sheets to
control layout and presentation
Technique 3.3.1 [priority 2] Check document
for use of style sheets.
- Elements: none (i.e. applies to all documents)
- Requirements: Document must contain at least one of the
following:
STYLE
or LINK rel="stylesheet"
elements within the HEAD
element | "style
"
attributes on any element | FONT
| BASEFONT
| "text," "vlink," "link," and "alink"
attributes on
BODY
.
- If layout tables are identified (see technique 5.1.1), trigger this
check as well. @@CR - Is this necessary? We will inform user that style sheets
can be used instead of layout tables in 5.1.1.
@@CR - We are suggesting that all documents require a style sheet. Is
this really necessary?
- Use style sheets to control layout and presentation. For example, use
the CSS '
font
' property instead of the HTML FONT
and BASEFONT
elements to
control font styles
- If style sheets are not used, verify that the author has chosen not
to modify the presentation in any way.
- If
FONT
or BASEFONT
elements or "text,"
"vlink," "link," and "alink"
attributes on BODY
,
suggest or help the author convert the presentation properties to style
sheets.
- If the author chooses to convert deprecated markup to style sheets or
add style sheets, trigger technique 6.1 to verify that the document is readable
when style sheets are not applied.
Checkpoint 3.4 - Use relative rather than
absolute units in markup language attribute values and style sheet property
values
Technique 3.4.1 [priority 2] Check
document for relative units of measure.
- Elements:
- "
style
" attribute on any element OR
STYLE
@@CR- STYLE itself does not have size parameters.
Remove?
- Requirements For any HTML or CSS element defined to take a
%LENGTH, %PIXELS, %MULTILENGTH
,
or %MULTILENGTHS
, (@@CR - we should list all of these) a validated value should
either end with "%" or begin with "+" or "-" or use the "em" or "ex"
units.
- Exception: "
width
" and "height
" attributes of IMG
elements.
@@CR - What about width & height of OBJECT and APPLET?
- This element uses absolute units of measure rather than relative
units of measure.
- Allow user to change the units of measure as follows:
- Allow user to specify which of the absolute sizes is the
default
- Automatically compute all others in terms of the default, with
choice of %, +/-, or em/ex @@LRK
Checkpoint 3.5 - Use header elements to
convey document structure and use them according to specification
Technique 3.5.1 [priority 2] Check
document for header nesting
- Elements:
Header
elements (H1-H6)
- Requirements: Header elements should nest according to the following
rules
- Header levels must not increase by more than 1 level. Example: H2
following H1 is good. H3 following H1 is bad.
- Header elements can decrease by any level. Example: H2 following
H5 is OK.
- Improper header nesting: Header levels must not increase by more than
one level per heading. Do not use headings to create font effects; use style
sheets to change font styles.
- Allow user to modify the header numbering within the document.
Technique 3.5.2 [priority 2] Check
document for missing header markup
- Element:
<P>
- Requirement: Paragraphs should be verified that they are not
headings. Potential headings can be identified by:
- Text elements occur within a paragraph AND
- The paragraph is less than 10 words AND
- The paragraph contains only text items or formatting elements
AND
- All text in the paragraph is formatted as bold and/or italics
and/or underline.
- Text has been identified that could possibly be a header. Is this
text used as a header: [potential header text]?
- Allow user to convert the text to a header.
Technique 3.5.3 [priority 2]
Verify that header elements are not used for formatting.
- Elements:
Header
elements (H1- H6)
- Requirement: If a header element's text content is longer than 20
words, query the user.
- Header elements (H1 - H6) should be used to define headers and should
not be used for formatting text.
- Allow the user to convert any header text to another type. Possible
types are:
- Paragraph
- Blockquote
Checkpoint 3.6 - Mark up lists and list
items properly
- Elements:
- Requirements
- Each
UL/OL/DL
tag must be followed by at least one LI
. (This
avoids the use of lists to create formatting e.g. via <UL><UL><UL>...
)
- Suspicious: a single
LI
, which may be used merely for
formatting
Not allowed: LI element used outside of an OL, UL, DIR, or
MENU element.
Not allowed: DT or DD element used outside of a DL
element @@LRK this is redundant with of "valid HTML" requirement
- List items should not be used for formatting text. Use Style sheets
or tables for formatting text.
- Allow the user to format the text within the LI element to another
element via a choice of
Checkpoint 3.7 - Mark up quotations. Do not use
quotation markup for formatting effects such as indentation
Technique 3.7.1 [priority 2] Verify
instances where quote markup should be used.
Q
is not supported in today's browsers, thus converting quotes
marks to Q
will basically delete the quote marks for all users. what do
we suggest in the meantime?
- Element:
<P>
[list of others?] elements
- Requirement: quote should be marked up with
Q
or BLOCKQUOTE
.
Potential quotes can be identified by:
- Any text that is enclosed by quote marks (" " or ' ').
- Indented text.
- Lots of emphasized text (>x words??)
- The following text may need to be marked using
Q
or BLOCKQUOTE
:
[potential quote text].
- Allow the user to convert blocks of text to
Q
or BLOCKQUOTE
.
Technique 3.7.2 [priority 2] Verify that
Q
and BLOCKQUOTE
are used properly
- Elements:
Q
and BLOCKQUOTE
- Requirement:
- Inline quotes (marked with
Q
) have at least one word in
front of, or behind, the quote text and are less than 10 words
- Long quotes (marked with
BLOCKQUOTE
) are greater than 10 words.
- If a block of text is marked as
BLOCKQUOTE
when it should be marked as
Q
: This text should be marked as Q
not BLOCKQUOTE
: [quote text].
- If a block of text is marked as
Q
when it should be marked as
BLOCKQUOTE
: This text should be marked as BLOCKQUOTE
not Q
: [quote text].
- Allow the user to convert blocks of text to
Q
or BLOCKQUOTE
or vice
versa.
Technique 3.7.3 [priority 2] Verify
that BLOCKQUOTE
is not used for formatting
- Element:
<BLOCKQUOTE>
- If text enclosed by BLOCKQUOTE has quote marks ("" or '') then do not
present this notification. @@??
- Nested
BLOCKQUOTE
s is not allowed.
- This text should be marked as normal text but formatted using style
sheets or a table.
BLOCKQUOTE
elements should be used to define quotes and should not be
used for formatting text.
- Allow the user to transform the text in the
BLOCKQUOTE
element into a
P
(paragraph) element.
- Checkpoint 4.1 - Clearly identify changes in
the natural language of a document's text and any text equivalents (e.g.,
captions)
- Checkpoint 4.2 - Specify the expansion of
each abbreviation or acronym in a document where it first occurs
- Checkpoint 4.3 - Identify the primary
natural language of a document
Checkpoint 4.1 - Clearly identify changes in
the natural language of a document's text and any text equivalents (e.g.,
captions)
- Element: none (i.e. applies to all documents that contain text)
- Requirement: The document must contain at least 3 words of text.
- Any words or phrases in a document that are not in the primary
language of the document should be identified.
- Display the above user notification and provide the following
suggestions:
- For blocks of text that are not in the primary language and are
already enclosed by markup elements such as
P
aragraph, DIV
or EM
,
set the "lang
" attribute of the markup element.
- For words or phrases that are not in the primary language,
enclose them with a
SPAN
element and set the SPAN
element's "lang
"
attribute.
- Ensure that all captions and other text equivalents are
checked.
Checkpoint 4.2 - Specify the expansion of
each abbreviation or acronym in a document where it first occurs
Technique 4.2.1 [priority 3] Verify that
abbreviations and acronyms need expanding.
- Elements: none (i.e. applies to all documents that contain text)
- Requirements:
- Document must contain at least 3 words.
- Document contains a potential abbreviation or acronym.
Definition of potential abbreviation:
- Any word greater than 2 characters that is all capital letters
Definition of potential acronym:
- Any word that starts with a capital letter, contains lower case
characters and ends with a period.
- A potential acronym/abbreviation has been discovered: [potential
acronym/abbreviation].
- Ask the user if the acronym or abbreviation was defined elsewhere on
the page and if so give the user the option to re-use it.
- Allow the user to enter a definition for the abbreviation of
acronym.
Checkpoint 4.3 - Identify the primary
natural language of a document
Technique 4.3.1 [priority 3] Verify the
primary language of the document
- Element:
<HTML>
- Requirements: Must contain a valid "
lang
" attribute
Definition of valid "lang
" attribute:
- Missing "
lang
" attribute: The primary language of this document
has not been set.
- Invalid "
lang
" attribute: The primary language of this document is
invalid.
- Prompt the user for the primary language of the document.
- Ensure that the language entered is one of the
ISO 639 language
codes.
- Checkpoint 5.1 - For data tables,
identify row and column headers
- Checkpoint 5.2 - For data tables that
have two or more logical levels of row or column headers, use markup to
associate data cells and header cells
- Checkpoint 5.3 - Do not use
tables for layout unless the table makes sense when linearized
- Checkpoint 5.4 - If a table is used for
layout, do not use any structural markup for the purpose of visual
formatting
- Checkpoint 5.5 - Provide summaries for
tables
- Checkpoint 5.6 - Provide
abbreviations for header labels
Checkpoint 5.1 - For data tables, identify
row and column headers
Technique 5.1.1 Determine the purpose of
the table
The purpose of the table must be determined before performing an
accessibility evaluation. To help the author make this assessment, the
following language may be used:
- Data tables present relational data such as a bus schedule, a
comparison of regional sales figures, or a listing of employee contact
information. Cells in data tables are related to each other and usually must be
perceived as a group.
- Layout tables visually format images, text, and other information on
the page such as a navigation bar, or a newspaper page with stories, links, and
images. Each cell in a layout table is normally independent and can be viewed
on its own.
Technique 5.1.2 [priority 1] Check
data table for row and column headers
- Element:
<TABLE>
.
- Requirement: the table must have at least one complete row of headers
or one complete column of headers.
- This technique applies only to tables used for data, not to tables
used for layout purposes.
- If both row and column headers are missing: Table is missing
headers.
- If either row or column headers are missing: Table has row/column
headers but may require column/row headers.
- Allow the user to modify the table to include row headers and/or
column headers.
- Allow the user to convert the top row and/or the left column to
headers.
- The user should create at least one complete row or one complete
column of headers.
Checkpoint 5.2 - For data tables that
have two or more logical levels of row or column headers, use markup to
associate data cells and header cells
Technique 5.2.1 - [Priority 1] Check
data tables for multiple levels of row and column headers
- Element:
<TH span=(2 or more)>
and either
- two or more
TR
elements containing at least one TH
- two or more
TH
elements within any TR
- Requirements:
- use of
SCOPE | AXIS | HEADER
- two or more rows containing
TH
OR
- two or more columns contain
TH
- Your table should identify structural groups of rows and groups of
columns. Label table elements with the "
scope
", "headers
", and "axis
"
attributes so that future browsers and assistive technologies will be able to
select data from your table by filtering on categories.
- If the table does contain 2 or more logical levels of row or column
headers, use the HTML 4 table
algorithm to show the author how the headers are currently associated with
the cells. If the author determines that the current mark-up is not sufficient,
allow the author to markup the table
TD
or TH
elements with scope
,
axis
, or headers
attributes.
Checkpoint 5.3 - Do not use
tables for layout unless the table makes sense when linearized
Technique 5.3.1 [priority 2] Verify
that layout tables make sense when linearized
- Element:
<TABLE>
- Requirement: Layout tables should make sense when linearized. This
technique applies only to tables used for layout purposes, not to data
tables.
- Tables used for layout should make sense when linearized.
- When a table is 'linearized,' the cells are read in the order in
which they appear in the HTML source.
- Linearize the table and ask the author to verify that the result is
understandable.
Checkpoint 5.4 - If a table is used for
layout, do not use any structural markup for the purpose of visual
formatting
Technique 5.4.1 [priority 2] Check layout
tables for structural markup
- Element:
<TABLE>
- Requirements: Contains at least one
TH
element. This technique
applies only to tables used for layout purposes, not to data tables.
- Tables used for layout should not use table headings to create
formatting effects.
- Allow user to change appearance of
TH
cells by
- style sheet properties
EM
and/or STRONG
Checkpoint 5.5 - Provide summaries for
tables
Technique 5.5.1 [priority 3] Check
TABLE
elements for valid "summary
" attribute
- Element:
<TABLE>
- Requirement: Must have valid "
summary
" attribute.
- If the table has nested headings, cells that span multiple columns or
rows, or other relationships that may not be obvious from analyzing the
structure of the table but that may be apparent in a visual rendering of the
table, a valid "
summary
" attribute may be provided. @@CR - All tables require
summary not just these ones.
Definition of valid "summary
" attribute:
- For missing summary - "Table is missing a summary." "In the summary,
describe the purpose of the table (either layout or data). For example ''This
table charts the number of cups of coffee consumed by each senator, the type of
coffee (decaf or regular), and whether taken with sugar.
- Additional help text: A summary of the relationships among cells is
especially important for tables with nested headings, cells that span multiple
columns or rows, or other relationships that may not be obvious from analyzing
the structure of the table but that may be apparent in a visual rendering of
the table. A summary may also describe how the table fits into the context of
the current document. If no caption is provided, it is even more critical to
provide a summary. @@CR- "Additional help" is beyond the scope of this
document.
- Allow the user to enter a summary of the table.
Checkpoint 5.6 - Provide abbreviations
for header labels
Technique 5.6.1 [priority 3] Check
table for header abbreviations
- How determine if an abbreviation is pronounceable? ASCII characters
only?
- Element:
<TH>
- Requirement: Valid "
abbr
" attribute if the header name is greater
than 15 characters.
Valid "abbr
" attributes:
- Not allowed - NULL "
abbr
" value ("")
- Not allowed - "
abbr
" value of spaces (" ")
- Suspicious - placeholder "
abbr
"
values
- "
abbr
" values should be shorter than 15 characters, but still
pronounceable.
- Table header is missing an abbreviation.
- Allow user to enter abbreviations for table header elements.
Guideline 6. Ensure that pages
featuring new technologies transform gracefully
- Checkpoint 6.1 - Organize
documents so they may be read without style sheets
- Checkpoint 6.2 - Ensure that
equivalents for dynamic content are updated when the dynamic content
changes
- Checkpoint 6.3 - Ensure that pages are usable
when scripts, applets, or other programmatic objects are turned off or not
supported
- Checkpoint 6.4 - For scripts and
applets, ensure that event handlers are input device-independent
- Checkpoint 6.5 - Ensure that dynamic
content is accessible or provide an alternative presentation or page
Checkpoint 6.1 - Organize
documents so they may be read without style sheets
Technique 6.1.1 [priority 1] Verify
that the document is readable when style sheets are not applied.
- Elements:
<LINK rel="stylesheet">
<STYLE>
- At least one "
style
" attribute used on any element.
- Ensure this document can be read without style sheets.
@@link to CSS module how to make readable.
- Display a user notification if any use of style sheets is
detected.
Checkpoint 6.2 - Ensure that
equivalents for dynamic content are updated when the dynamic content
changes
Technique 6.2.1 [priority 1] Check
the source of FRAME
and IFRAME
elements for valid markup files.
- Elements:
FRAME
or IFRAME
- Requirements:
- Valid "
src
" attribute values must have a suffix of ".htm,"
".html," ".shtm," ".shtml," ".cfm," ".cfml," ".asp," ".cgi," ".pl" (@@what
are the extensions for SMIL and MathML files?) or target document must
have a known public identifier at the top of file.
- Frame source: [frame source file name] is not a valid markup
file.
- Create an HTML "wrapper" around known object types, e.g. if the
target is an image, place the image in an HTML file.
- Adjust Javascript to point inside the wrapper @@LRK:
(yikes you say? well, we can ask...)
Technique 6.2.2 [priority 1]
Verify that equivalents of dynamic content are updated and available as often
as the dynamic content.
@@is that really what we want to say here? This gets into issues
related to Guideline 7. I guess we could tie them together in some
way...?
- Elements:
SCRIPT,
APPLET, OBJECT
type=@@?
, any_element event_attribute
where event_attribute is "onmouseover" etc.
- Requirements: any actions that change the display must change the
equivalent @@LRK::Is this computable in a practical time (cf. NP complete) .
Computer science help needed here. Of course, as in other parts of
document, the fact that the equivalent changes is no guarantee that equivalent
is correct than it is guaranteed that
"alt"
text for an image is
correct.
- Ensure that the descriptions of dynamic content are updated with
changes in the dynamic content.
Checkpoint 6.3 - Ensure that pages are usable
when scripts, applets, or other programmatic objects are turned off or not
supported
Technique 6.3.1 [priority
1] Verify that the page is usable when programmatic objects are disabled.
- Elements:
SCRIPT @@CR- covered in 1.1.11, OBJECT type=@@?, EMBED, APPLET
- Requirements: existence of "
alt
" and/or "title"
and/OR contained
alternatives, as appropriate. @@contained alternatives?? @@CR- Alt & Title
are not enough. This calls for alternate content
- Between the start and end elements must be an accessible alternative
representation of the object.
- Ensure that pages are usable when scripts, applets, or other
programmatic objects are turned off or not supported.
- Provide means to create an accessible alternative representation or
provide a link to one.
Checkpoint 6.4 - For scripts and
applets, ensure that event handlers are input device-independent
Technique 6.4.1 [priority 2]
Check for device independent event handlers.
- Elements:
SCRIPT, OBJECT type=@@?, EMBED, APPLET
- Requirements: Objects must not contain device dependent event
handlers. @@LRK: need help here. @@CR- Yikes, must we parse Java and script
code?
- For scripts and applets, ensure that event handlers are input
device-independent.
- Display object source code and suggest device independent replacement
code.
Checkpoint 6.5 - Ensure that dynamic
content is accessible or provide an alternative presentation or page
Technique 6.5.1 [priority 2] Check
that a NOFRAMES
element exists within each FRAMESET
.
- Element:
<FRAMESET>
- Requirements:
- A valid
NOFRAMES
section should exist within each FRAMESET
section
Definition of valid NOFRAMES
section
- Must contain at least one word of text or accessible HTML code.
- The contents of the
NOFRAMES
element must allow the user access to the
site. @@CR- I'm not sure what this means?
- Not allowed: Telling the user that they should upgrade to a browser
that supports frames. Suspicious words within the text of a
NOFRAMES
element:
"upgrade," "full advantage," supports frames," "missing" etc.
- Does your page work if frames are not loaded?
- Allow user to construct a valid
NOFRAMES
section.
@@CR - Isn't this covered by 6.3.1 (Verify that the page is usable when
programmatic objects are disabled)?
Guideline 7. Ensure user control of
time-sensitive content changes
- Checkpoint 7.1 - Until user agents allow
users to control flickering, avoid causing the screen to flicker.
- Checkpoint 7.2 - Until user agents allow
users to control blinking, avoid causing content to blink
- Checkpoint 7.3 - Until user agents
allow users to freeze moving content, avoid movement in pages
- Checkpoint 7.4 - Until user agents
provide the ability to stop the refresh, do not create periodically
auto-refreshing pages
- Checkpoint 7.5 - Until user agents
provide the ability to stop auto-redirect, do not use markup to redirect pages
automatically
Checkpoint 7.1 - Until user agents allow
users to control flickering, avoid causing the screen to flicker
Technique 7.1.1 [priority 1] Verify that the
page does not cause flicker.
- It is desirable that a tool be able to measure flicker. This could be
done by software that renders, takes screenshots and compares. [Len
Kasday, 23 January 2000]
- Elements:
<SCRIPT>
<OBJECT type =>
(@@what are the type attribute values for Java,
etc.?)
<EMBED>
<APPLET>
<IMG>
element with "src
" name ending with '.gif'.
- Display flicker is distracting and may be dangerous to some users.
Please ensure this element does not cause the display to flicker.
- Display the object and allow the user to verify that it does not
cause display flicker. If object does cause flicker, allow user to modify
object.
Checkpoint 7.2 - Until user agents allow
users to control blinking, avoid causing content to blink
Technique 7.2.1 [priority 1] Check for BLINK
elements
- The
BLINK
element is not defined in any W3C HTML specification and
should not be used.
- Allow the user to remove
BLINK
elements from the document.
- Allow the user to replace
BLINK
elements with any of the following
elements:
STRONG
EM
SPAN
- allow the user to enter attributes for the element.
H1
H2
H3
H4
H5
H6
Checkpoint 7.3 - Until user agents
allow users to freeze moving content, avoid movement in pages
Technique 7.3.1 [priority 1] Check for
MARQUEE
elements
- The
MARQUEE
element is not defined in any W3C HTML specification and
should not be used.
- Allow the user to remove
MARQUEE
elements from the document.
- Allow the user to replace
MARQUEE
elements with any of the following
elements:
STRONG
EM
SPAN
- allow the user to enter attributes for the
element.
H1
H2
H3
H4
H5
H6
Technique 7.3.2 [priority 1]
Verify that programmatic objects do not create moving content
- Elements:
SCRIPT
- distinguished by (see discussion)??
OBJECT type =
(@@what are the type attribute values for Java,
etc.?)
EMBED
APPLET
- Moving text may be difficult to read and is inaccessible for many
viewers.
- Allow the user to remove the
SCRIPT
from the document or create a
mechanism to stop the movement.
- @@ what about
OBJECT, EMBED, and APPLET
?
Checkpoint 7.4 - Until user agents
provide the ability to stop the refresh, do not create periodically
auto-refreshing pages
Technique 7.4.A [priority 2] Remove
auto-refresh attributes from META
elements
- Elements:
META http-equiv="refresh"
content=
integer_greater_than_zero
- Note:If the "
content
" attribute is a URI this is an auto-redirect
page. Refer to technique 7.5.1
- This page uses auto-refresh which can make the page difficult to read
for some people.
- Allow user option to either:
- Remove the auto-refresh from the document OR
- Create a page with link to new page.
Checkpoint 7.5 - Until user agents
provide the ability to stop auto-redirect, do not use markup to redirect pages
automatically
Technique 7.5.1 [priority 2] Check
auto-redirect attributes on META
elements
- Element:
<META http-equiv="refresh"
content="
any-URI
">
.
- This page uses auto-redirect which can make the page difficult to
read for some people.
- Allow the user to remove the auto-redirect from the document and add
a link to the new document.
Guideline 8. Ensure direct accessibility
of embedded user interfaces
Checkpoint 8.1 - Make programmatic
elements such as scripts and applets directly accessible or compatible with
assistive technologies
Technique 8.1.1
[priority 1 if functionality is important and not presented elsewhere,
otherwise Priority 2] Verify that programmatic objects are directly
accessible.
- Tools should include means to test the embedded technologies, e.g.
java, at least by running them, preferably by including any test software
supplied for the technology. [Len
Kasday - 23 January 2000]
- Elements:
OBJECT, APPLET
, EMBED or SCRIPT
.
- This element may not be accessible to all users. Please ensure there
is an accessible interface to this object.
- Ensure that scripts, applets, or other programmatic objects are
directly accessible
- Display a user notification if any of the programmatic elements are
in the document.
Guideline 9. Design for
device-independence
- Checkpoint 9.1 - Provide client-side
image maps instead of server-side image maps except where the regions cannot be
defined with an available geometric shape.
- Checkpoint 9.2 - Ensure that any
element that has its own interface can be operated in a device-independent
manner.
- Checkpoint 9.3 - For
scripts, specify logical event handlers rather than device-dependent event
handlers.
- Checkpoint 9.4 - Create a logical tab
order through links, form controls, and objects.
- Checkpoint 9.5 - Provide keyboard
shortcuts to important links, form controls, and groups of form controls
Checkpoint 9.1 - Provide client-side
image maps instead of server-side image maps except where the regions cannot be
defined with an available geometric shape
Technique 9.1.1 [priority 1] Check
for use of server-side image maps
- Use client-side image maps instead of server-side maps.
- Allow the user to convert the server-side image map to a client-side
image map.
Checkpoint 9.2 - Ensure that any
element that has its own interface can be operated in a device-independent
manner
(Image map text links - checked in techniques 1.2.A and 1.5.A.
@@Programmatic objects check in 6.5 and 8.1.A Need clarification.
Strongly tied to Guideline 8.
- Elements:
OBJECT type =
(@@what are the type attribute values for Java,
etc.?)
EMBED
APPLET
- Ensure this programmatic object can be operated in a device
independent manner.
- Display a user notification if any of the programmatic objects are in
the document.
Checkpoint 9.3 - For scripts,
specify logical event handlers rather than device-dependent event handlers
Technique 9.3.1 [priority 2]
Check scripts for logical event handlers
- Elements: All elements that can contain event handlers
- Requirement: Elements must have a device independent event handler if
they have any of the following device dependent event handlers:
onMouseDown()
onMouseUp()
onClick()
onMouseOver()
onMouseOut()
onMouseMove()
- For scripts, specify logical event handlers rather than
device-dependent event handlers.
Allow the user to add or replace the event handlers according to the
following list:
- "
onMouseDown
" add or replace with "onKeyDown
"
- "
onMouseUp
" add or replace with "onKeyUp
"
- "
onClick
" add or replace with "onKeyPress
"
- "
onMouseOver
" add or replace with "onFocus
"
- "
onMouseOut
" add or replace with "onBlur
"
- "
onMouseMove
" remove or replace with ??@@
Checkpoint 9.4 - Create a logical tab
order through links, form controls, and objects
- Elements:
<A>
<AREA>
<BUTTON>
<INPUT>
<OBJECT>
<SELECT>
<TEXTAREA>
- Requirements:
- Must contain a valid "
tabindex
" attribute. @@CR- Can this be
optional?
Definition of valid "tabindex
" attribute:
- Must be an integer greater than or equal to zero.
- These controls are missing a tab order. A tab order makes controls
easier to navigate for many users.
@@LRK:: Issue: if the tabindex jumps around too much it could be
confusing to someone using magnification or a cognitive disability.
- Display the controls and allow the user to set the tabindex of
each.
Checkpoint 9.5 - Provide keyboard
shortcuts to important links, form controls, and groups of form controls
- Elements:
<A>
<AREA>
<BUTTON>
<INPUT>
<LABEL>
<LEGEND>
<TEXTAREA>
- Requirements:
- If any of these elements are present, at least one of them should
have a valid "
accesskey
" attribute
- There are no keyboard shortcut keys to any of the controls in this
document. Important links and controls should have shortcut keys.
Suggested repair:
- Display the objects that can contain shortcut keys and allow the user
to assign shortcut keys to them.
- Checkpoint 10.1 - Until user agents
allow users to turn off spawned windows, do not cause pop-ups or other windows
to appear and do not change the current window without informing the user
- Checkpoint 10.2 - Until user
agents support explicit associations between labels and form controls, for all
form controls with implicitly associated labels, ensure that the label is
properly positioned
- Checkpoint 10.3 - Until user agents
(including assistive technologies) render side-by-side text correctly, provide
a linear text alternative (on the current page or some other) for all tables
that lay out text in parallel, word-wrapped columns
- Checkpoint 10.4 - Until user agents
handle empty controls correctly, include default, place-holding characters in
edit boxes and text areas
- Checkpoint 10.5 - Until user agents
(including assistive technologies) render adjacent links distinctly, include
non-link, printable characters (surrounded by spaces) between adjacent
links
Checkpoint 10.1 - Until user agents allow
users to turn off spawned windows, do not cause pop-ups or other windows to
appear and do not change the current window without informing the user
Technique 10.1.1 [priority 1] Check
A
and AREA
elements for valid "target
" attributes
- @@ how do we handle the "until user agents" clause?
- Elements:
- Requirements:
- Should not have "
target
" attributes of "_blank
" or
"_new
".
- This anchor element [anchor text] will open a new window that can
disorient some users.
- Allow the user to
- remove the "
target
" attribute or
- use an existing window as the target
- @@CR - If the document informs the user that the link will open
in a new window is that enough?
- Elements:
SCRIPT
APPLET
- @@other embedded scripting languages?
- Requirement:
SCRIPT
must not contain code of window.open()
- @@CR - All applets get warning message?
- This script will open a new window that can be disorienting for some
users.
- Allow the user to remove the scripting code that opens a new
window.
@@CR - got to here
Checkpoint 10.2 - Until user agents
support explicit associations between labels and form controls, for all form
controls with implicitly associated labels, ensure that the label is properly
positioned
Refer also to checkpoint 12.4
- Elements:
- Requirement: A label for a text area, a text input control or group
of controls (e.g., a group of checkboxes) must immediately precede its control
(or group of controls) on the same line (if there is only one control or group)
or be in the line preceding the control (or group of controls).
- A label for a text area, a text input control or group of controls
(e.g., a group of checkboxes) must immediately precede its control (or group of
controls) on the same line (if there is only one control or group) or be in the
line preceding the control (or group of controls).
- Allow the user to reposition labels associated with form controls as
follows:
- Labels for radio buttons and checkboxes should appear after the
radio button or checkbox. For example: [checkbox] oranges, [checkbox]
apples.
- Labels for text fields appear before the text field. For example:
last name [text area].
- Labels for groups of any form control should appear before the
group. For example: choose a city [radio button] Boston [radio button]
Madison.
Checkpoint 10.3 - Until user agents
(including assistive technologies) render side-by-side text correctly, provide
a linear text alternative (on the current page or some other) for all tables
that lay out text in parallel, word-wrapped columns
- Element:
<TABLE>
- Requirement: A linear version of the table is provided
- Please consult the definition of linearized table. This checkpoint
benefits people with user agents (such as some screen readers) that are unable
to handle blocks of text presented side-by-side; the checkpoint should not
discourage content developers from using tables to represent tabular
information.
- If it has been determined that the table is used for layout (see
Technique 5.1.1) then create a linear version of the table by: [@@insert
heuristics from table linearizer - basically replace
TABLE
markup with text
structural markup]. The author will then need to check that it is
readable.
- If it has been determined that the table is used for data (see
Technique 5.1.1) then create a linear version of the table by: [@@table
linearizer heuristics? basically, for each cell repeat the column and row
headers associated with it]. The author will then need to check that it is
readable.
- Table linearizer
- Trace "HelpDB"
- other examples
Checkpoint 10.4 - Until user agents handle
empty controls correctly, include default, place-holding characters in edit
boxes and text areas
- Elements:
- Requirements
- Check
INPUT type="text"
for valid "value
" attribute.
- Check
INPUT type="checkbox" | "radio"
with the same "name
" attribute for one of them
to have a "selected
" attribute.
- Check
TEXTAREA
for valid text content.
- Check all
OPTION
s in a SELECT
element for one of them to have a
"selected
" attribute.
- For
INPUT type="text"
and TEXTAREA
elements, ask the user for default text or
suggest a space.
- For groups of radio buttons, checkboxes, and selection boxes, ask the
user to pick one to be the default.
Checkpoint 10.5 - Until user agents
(including assistive technologies) render adjacent links distinctly, include
non-link, printable characters (surrounded by spaces) between adjacent
links
- Element:
<A>
- Requirement: Check for at least one non-whitespace character
surrounded by at least one whitespace character between every close
A
and
open A
element. Whitespace is a space, tab, CR, or
- Suggest that the author select to use vertical bars "|" between
A
elements, but allow them to choose another character if they prefer.
Insert the selected character surrounded by white space between each </A>
and
<A>
element.
Guideline 11. Use W3C technologies and
guidelines
- Checkpoint 11.1 - Use W3C
technologies when they are available and appropriate for a task and use the
latest versions when supported
- Checkpoint 11.2 - Avoid deprecated
features of W3C technologies
- Checkpoint 11.3 - Provide
information so that users may receive documents according to their
preferences
- Checkpoint 11.4 - If, after best efforts,
you cannot create an accessible page, provide a link to an alternative page
that uses W3C technologies, is accessible, has equivalent information (or
functionality), and is updated as often as the inaccessible (original)
page
Checkpoint 11.1 - Use W3C technologies
when they are available and appropriate for a task and use the latest versions
when supported
- Element: ?@@
- Requirements:
- Check for uses of non-W3C technologies such as: PDF, Flash, GIF
images, JPG images, proprietary HTML elements (@@other major ones??).
- @@See 1.1.1 for images used for mathematical equations.
- Note. I left out JavaScript because there is not a W3C equivalent
technology yet.
- Non-W3C technology used: W3C technologies have been reviewed for
accessibility issues throughout the design phase and have accessibility
built-in. Many non-W3C formats require specific applications (often called
plug-ins) that are inaccessible or do not work well with assistive
technologies. Using W3C technologies will tend to make pages more accessible to
more people using a wider variety of hardware and software. If inaccessible
technologies (proprietary or not) must be used, equivalent accessible pages
must be provided.
- Suggest that where appropriate, the author:
- convert quicktime movies (others?) into SMIL presentations.
- convert GIF and JPG images with text to text with style
sheets.
- convert Flash animations to a combination of valid HTML, SMIL,
and PNG or SVG.
- @@convert images of math equations to MathML.
- @@Note: many of these W3C formats are not widely supported yet.
Therefore, how do we deal with this in the meantime? Present the info and let
the author decide?
- Use a text-only page generator (such as Adobe's PDFtoText) to create
an equivalent accessible page.
Checkpoint 11.2 - Avoid deprecated
features of W3C technologies
- Elements:
APPLET, BASEFONT, CENTER, DIR, FONT, ISINDEX, MENU, S,
STRIKE
, and U
. (Refer to the
list
of deprecated elements in the HTML 4.01 specification.)
- Requirements:
- Use W3C validation services to validate documents as per their
public text identifier.
- See checkpoint 3.2 for more information on public text
identifiers.
- Use of deprecated HTML element: you are validating against [public
text identifier] and the following elements have been deprecated in favor of
newer elements. [insert list of deprecated elements used in the page with what
they should be replaced with].
- Help the author replace
FONT
with use of CSS
.
- Help the author replace
IMG
and APPLET
with OBJECT
.
- @@Others?
Checkpoint 11.3 - Provide
information so that users may receive documents according to their
preferences
- Element: ?@@
- Requirement: ?@@
- Prompt user to specify language of document in
technique 4.3.1.
- Use CC/PP or XML/XSLT or other transformations on the server or
gateway to configure a page for various user preferences and device
profiles.
- Serve style sheets based on user preferences - use the media
types.
- Work with your server system administrator to provide content
negotiation.
- Use browser sniffing on the client to request documents on the
server.
- Use cookies to remember user preferences between sessions and server
documents per those preferences.
- Link to other versions of the document (other formats and
languages).
- If not possible to use content negotiation, indicate content type or
language through markup (e.g., in HTML use "
type
" and "hreflang
").
Checkpoint 11.4 - If, after best efforts, you
cannot create an accessible page, provide a link to an alternative page that
uses W3C technologies, is accessible, has equivalent information (or
functionality), and is updated as often as the inaccessible (original)
page
- Elements: not applicable
- Requirements: For each page, keep track of which checkpoints the
author has passed, either through automatic evaluation or confirmed through
prompting the author. Ask what level of conformance the author is trying to
reach. If checkpoints for that level have not yet been met, ask the author if
they would like to continue working to make the page accessible. If they do
not, ask them if they would like to provide an alternative, accessible
page.
- Before resorting to an alternative page, reconsider the design of the
original page; making it accessible is likely to improve it for all users.
- Dynamically generated alternative pages [references@@].
- Tools to generate alternative pages [references@@].
Guideline 12. Provide context and
orientation information
- Checkpoint 12.1 - Title each frame to
facilitate frame identification and navigation
- Checkpoint 12.2 - Describe the purpose
of frames and how frames relate to each other if it is not obvious by frame
titles alone
- Checkpoint 12.3 - Divide large
blocks of information into more manageable groups where natural and
appropriate
- Checkpoint 12.4 - Associate labels
explicitly with their controls
Checkpoint 12.1 - Title each frame to
facilitate frame identification and navigation
Technique 12.1.1 [priority 1] Check FRAME
elements for valid "title
" attributes
- Element:
<FRAME>
- Requirement:a
FRAME
element must have valid "title
" attribute
- Missing title for this frame: [frame file name].
- Prompt user for frame title.
Checkpoint 12.2 - Describe the purpose of
frames and how frames relate to each other if it is not obvious by frame titles
alone
@@ isn't this covered by 1.1.8?
(Suggest that if the frame title does not describe the frame that a
"longdesc
" is needed?)
Checkpoint 12.3 - Divide large blocks
of information into more manageable groups where natural and appropriate
(@@Any suggestions??)
Checkpoint 12.4 - Associate labels
explicitly with their controls
- Element:
<INPUT>
- Requirement: Check that the "
for
" attribute value of a LABEL
element matches the "id
" value of a form control on the current page.
- Form controls are not explicitly labeled.
- If a
LABEL
does not have a valid "for
" attribute, list all of
the controls without explicitly associated labels and let the author pick
one.
- If a form control does not have a
LABEL
, verify that the author has
implicitly associated text with the form control then help the author convert
associated text into a LABEL
element.
Guideline 13. Provide clear
navigation mechanisms
- Checkpoint 13.1 - Clearly identify
the target of each link
- Checkpoint 13.2 - Provide metadata to add
semantic information to pages and sites
- Checkpoint 13.3 - Provide information
about the general layout of a site
- Checkpoint 13.4 - Use navigation
mechanisms in a consistent manner
- Checkpoint 13.5 - Provide navigation bars to
highlight and give access to the navigation mechanism
- Checkpoint 13.6 - Group related links,
identify the group (for user agents), and, until user agents do so, provide a
way to bypass the group
- Checkpoint 13.7 - If search functions are
provided, enable different types of searches for different skill levels and
preferences
- Checkpoint 13.8 - Place distinguishing
information at the beginning of headings, paragraphs, lists, etc
- Checkpoint 13.9 - Provide information
about document collections
- Checkpoint 13.10 - Provide a means to
skip over multi-line ASCII art
Checkpoint 13.1 - Clearly identify the
target of each link
- Element:
<A>
- Requirements:
- Check for commonly used non-meaningful phrases such as "click
here" and "more" as link text.
- Check that if link text is not unique, duplicates link to the
same place.
- Link text should be meaningful enough to make sense when read out of
context -- either on its own or as part of a sequence of links. Link text
should also be terse.
- Retrieve the
TITLE
of the target page and suggest that as link
text.
- If the author is trying to make a Level Triple A site, Ask the author
to provide supplemental information about the link in the "
title
"
attribute.
Harper, S., Stevens, R., and Goble, C. (1999). Towel: Real World
Mobility on the Web. In Vanderdonckt, J. and Puerta, A., eds.: Computer-Aided
Design of User Interfaces II. Dordrecht, Netherlands: Kluwer Academic
Publishers.
Checkpoint 13.2 - Provide metadata to add
semantic information to pages and sites
- Elements:
- Requirements: Check for
META, ADDRESS, TITLE
and LINK
elements in the HEAD
element of HTML/XHTML files.
- If no
META, ADDRESS, TITLE
or LINK
elements are found, request information from
the author to be stored as meta information. Examples of content to prompt for:
- title of the page (required for frames, see checkpoint
12.1),
- type of content,
- descriptions of the content of the page,
- conformance claims,
- author information,
- next page in a series (e.g.,
LINK rel="next"
).
- If a
LINK
element is found, check if it is used for style sheets.
If it is, then proceed as if no LINK
element were found.
- If a
META
element is found, check if it is used to create a
redirect. If it is, then proceed as if no META
element were found (refer
also to checkpoints 7.4 and 7.5).
@@Similar to 13.2.1, yet might be best in own technique??
Checkpoint 13.3 - Provide information
about the general layout of a site
(@@Can't be machine checked. User notification?)
Checkpoint 13.4 - Use navigation
mechanisms in a consistent manner
- Elements: Not applicable
- Requirements: Not applicable
(@@Can't be machine checked. User notification?)
Checkpoint 13.5 - Provide navigation bars to
highlight and give access to the navigation mechanism
(@@Can't be machine checked. User notification?)
Checkpoint 13.6 - Group related links,
identify the group (for user agents), and, until user agents do so, provide a
way to bypass the group
This suggests another technique that is not widely supported by user
agents.
- Element: Several
<A>
elements all in one row or column of table
and/or separated only by
BR
elements,
- or a few characters such as "] [" or " | " or
- Requirement: links should be grouped by
SPAN,DIV
or MAP
elements.
@@DIV or SPAN?
- Groups of links should be grouped with a structural element.
- Ask the user if an identified list of links should be grouped.
- If the user wants to group the links, use one of the following
techniques
- a
MAP
element (@@still outstanding issues in WCAG w/this
technique?)
SPAN
or DIV
with appropriate "title
" @@??
- Suggest that the user provide a link to bypass the group or that they
move the group to the bottom of the page or that they use a high "
tabindex
"
attribute value.
Checkpoint 13.7 - If search functions are
provided, enable different types of searches for different skill levels and
preferences
- Element:
<FORM>
- Requirement: Check if a
FORM
is used to submit a search.
- When providing search functionality, content developers should offer
search mechanisms that satisfy varying skill levels and preferences. Most
search facilities require the user to enter keywords for search terms. Users
with spelling disabilities and users unfamiliar with the language of your site
will have a difficult time finding what they need if the search requires
perfect spelling. Search engines might include a spell checker, offer "best
guess" alternatives, query-by-example searches, similarity searches, etc.
Checkpoint 13.8 - Place distinguishing
information at the beginning of headings, paragraphs, lists, etc
@@(Can't be machine checked. User notification?)
Checkpoint 13.9 - Provide information
about document collections
- @@Way to use RDF to describe document collections?
- Elements: @@?
LINK, A
- Requirement: If the page is part of a collection, such as a slide
show, or a chapter in a book, the previous and next pages ought to be marked as
such.
- Bundled documents can facilitate reading off-line.
- In HTML/XHTML specify document collections with the
LINK
element
and the "rel
" and "rev
" attributes.
- Suggest that that the author create a collection by building an
archive (e.g., with zip, tar and gzip, stuffit, etc.) of the multiple
pages.
Checkpoint 13.10 - Provide a means to
skip over multi-line ASCII art
- @@This is a new technique
- Can't be machine checked - this sort of ASCII art is larger than just
emoticons. User notification?
- Elements: not applicable
- Requirements: no heuristically found ACSII art @@LRK need
heuristics
- If this is a picture made of of text characters, it isn't
accessible
- Provide description of ASCII art and a link to skip past it
- perhaps make description invisible e.g. as using the
"alt"
attribute of a transparent image
- In future, wrap in
DIV
with descriptive "title
"
- Provide means to convert
AREA
to IMG
with "alt"
attribute
Guideline 14. Ensure that
documents are clear and simple
- Checkpoint 14.1 - Use the clearest and
simplest language appropriate for a site's content
- Checkpoint 14.2 - Supplement text with graphic
or auditory presentations where they will facilitate comprehension of the
page
- Checkpoint 14.3 - Create a style of
presentation that is consistent across pages
Checkpoint 14.1 - Use the clearest and
simplest language appropriate for a site's content
@@(Check document using fog index? User notification?)
Checkpoint 14.2 - Supplement text with graphic or
auditory presentations where they will facilitate comprehension of the
page
@@ (Can't be machine checked. User notification?)
Checkpoint 14.3 - Create a style of
presentation that is consistent across pages
- @@this requires looking at pages throughout the site. Need two levels
of checking: page vs site?
- Elements:
STYLE
and LINK
- Requirements:
- The properties of
STYLE
elements should be consistent between
pages.
- The names of external style sheets (referenced with
LINK
elements) should be consistent between pages.
- This should be verified by the author. There are good reasons to
use different styles between pages.
- Consistent page layout and recognizable graphics benefit all users.
In particular, they help people with cognitive disabilities or who have
difficulty reading.
- If style properties vary between pages, or various external style
sheets are used, suggest the author consolidate style properties into external
style sheets and use consistently.
After evaluating a document, an evaluation and/or repair tool should
provide the user with a document rating. The rating is based on conformance to
the W3C Web Content
Accessibility Guidelines and will be:
- Level "A": all Priority 1 checkpoints are
satisfied;
- Level "Double-A": all Priority 1 and 2 checkpoints
are satisfied;
- Level "Triple-A": all Priority 1, 2, and 3
checkpoints are satisfied;
Some checkpoints can not be checked by a software program and will
require user evaluation. The user must be informed of the items that they must
check.
Refer to the Rating
Algorithm for Evaluation of Web Pages by Len Kasday.
- an image file suffix (see Appendix B)
- the single word "Image", "Photo"
- the word "images" (e.g. as in "turn on images").
Appendix B - Image File
Suffixes
Appendix C - Placeholder OBJECT
text equivalent
Appendix D - Sound File
Suffixes
- .wav
- .au
- .snd
- .dwd
- .iff
- .svx
- .sam
- .smp
- .vce
- .voc
- .pcm
- .aif
Appendix E - Placeholder
NOSCRIPT
text
- {NOSCRIPT text goes here}
Appendix F - Placeholder TABLE
"summary"
text
- Summary
- Table
- Table Summary
Appendix G - Placeholder table
header "abbr
" text
Appendix H - Placeholder FRAME
"title"
text
Appendix I - Applet Executable
Suffix
Appendix J - Bullet
Identification
An image will be identified as a bullet if it has the following
characteristics:
Identifying Bullets
page
Appendix K - Horizontal Rule
Identification
An image will be identified as a horizontal rule if it has the following
characteristics:
Identifying HRs
page
Appendix L - Links To
Associated Sites
- Bobby - Accessibility
evaluator tool
- Lynx Viewer -
Displays a text-only view of web pages
- A-Prompt -
Accessibility evaluator and repair tool
- Programmatic object
- An object that is embedded in a document with the SCRIPT or
APPLET
elements, and sometimes with the OBJECT or EMBED elements. @@need to clarify
the definition and then use it.
@@Copyright info? it's at the top...