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 methods 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 test condition:
- 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.
- Example of a message to be displayed:
- Messages displayed to the author if the element is found and the
requirement is not satisfied.
- Additional actions:
- Further action to be taken if the element is found and the requirement
is not satisfied.
- 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>
- Requirements:
"alt"
attribute is valid
Definition of 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 (any valid URI) 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.
- Cases where a description is not required:
- 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:
"alt"
attribute is valid.
Definition of valid vs. invalid value for "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>
- Requirement:
- 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 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 Additional actions: 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: none
- 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
- Elements:
<OBJECT type=
Audio or Video MIME
TYPE
>
- Requirement: There must be text or other accessible HTML between the
start and end tag (recursively check embedded
OBJECT
s)
- Embedded Audio files must provide accessible text or other accessible
HTML.
- Prompt user for text transcript of audio 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
" 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
- Requirement:
NOSCRIPT
element before end tag AND
- Accessible HTML following the
NOSCRIPT
element.
"Accessible" means apply all tests in this document. @@LRK: changed
"text" to "Accessible HTML". I'm going to continue doing that for the
rest, but silently.
Example of a message to be displayed:
- Language for missing
NOSCRIPT
: Missing
NOSCRIPT
element for this SCRIPT
element.
- If contained HTML not accessible:
NOSCRIPT
contains
inaccessible HTML (followed by messages corresponding to problems)
- Insert
NOSCRIPT
- Provide means to insert text, hand coded HTML, or HTML imported from
specified Editor @@LRK added
@@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.
@@Note: We are still working on methods of determining if a document
contains ASCII art. If we can't find a suitable algorithm that finds ASCII art
then all pages will get a notification.
ASCII Art Discussion
Page
- If there is any ASCII art in this document then please give it a textual
description.
- Prompt user for descriptions of any ASCII art contained in the
document.
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: valid "
ismap
" attribute must be a valid
URI
- 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.
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.
- 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 textstream 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: 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
.
Valid "usemap
" attribute:
- Client-side image maps should have associated text links.
- Ask the user if there are associated text links for this image map.
- If there are not associated text links, allow the user to create
them.
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).
- Requirement: @@
- 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).
- The user notification will be displayed 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 offending colors.
- 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
- Requirement: @@?
- 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
-
- The user notification will be generated for each document.
- Help authors convert decorative ascii art in PRE elements to SVG or an
image format.
- Help authors convert ascii art represeting 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:
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.
- Requirements: convert deprecated presentation elements to style sheets
where appropriate.
- 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 none of these elements are identified, 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
- Requirements For any HTML or CSS element defined to take a
%LENGTH, %PIXELS, %MULTILENGTH
, or
%MULTILENGTHS
, 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.
- 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 if
your audience has browsers that support CSS positioning. Otherwise use
Tables for now.
- 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 the 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.
- Requirement: @@
- Any words or phrases in a document that are not in the primary language
of the document should be identified.
- Display the above warning 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 (this message always)
- Requirements: none (these test always shown)
- Scan the document for any of these patterns
- Two or more upper case letters in a row between white space or
punctuation
- The following sequence:
- white space
- upper case letter
- one or more lower case letters
- a period
- white space or punctuation
- If any of these patterns are found,
- If the acronym or abbreviation was defined elsewhere on the page,
give the user the option to re-use it. Otherwise:
- Ask the user: is this an abbreviation, an acronym, or neither?
- If it is an acronym or abbreviation, prompt the user to enter the
definition.
Checkpoint 4.3 - Identify the
primary natural language of a document
Technique 4.3.1 [priority 3] Verify the primary
language of the document
HTML
element must contain a valid "lang
"
attribute
Allowed LANG
attributes:
- 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 the
table for row and column headers
- Element:
TABLE
.
- Requirement: the table must have at least one complete row of headers
and 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 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
elments 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
with one or more TH
and the
table is a layout table (as identified in 5.1.1).
- Requirements:
TH
elements should not be used in layout
tables.
- Tables used for layout should use table headings to create formatting
effects.
- Allow user to change appearance of 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
element that has and no
"summary
" attribute.
- Requirement: 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.
Valid "summary
" attribute:
- For missing summary - "Table is missing a summary."
- Suggested prompt to user - "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.
- for table where it is difficult to determine the relationship among
cells. A summary is especially important for tables with , or
- Allow the user to enter a summary of the table.
- Element:
TABLE
- Requirement@@???
- Verify that the TABLE element should have a valid CAPTION element.
- This
TABLE
does not have a CAPTION
: A table
caption describes the nature of the table in one to three sentences. For
example, "Cups of coffee consumed by each senator."
- Allow the author to enter a
CAPTION
.
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
element,
- At least one "
style
" attribute used on any
element.
- Requirement: The document must be readable when style sheets are not
applied. @@link to CSS module how to make readable.
- Ensure this document can be read without stylesheets.
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:
- contents of element must be HTML, XHTML, SMIL, MathML, or other
valid markup
- 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 have a known public identifier at the top of file.
- Frame source: [frame source file name] is not a valid markup file.
- Provide and insert an HTML "wrapper", e.g. if the contents of the file
was an image, replace with
IMG
containing that image.
- 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, OBJECT type=@@?, EMBED, APPLET
- Requirements: existence of
"alt"
and/or
"title"
and/OR contained alternatives, as appropriate.
@@contained alternatives??
- Ensure that pages are usable when scripts, applets, or other
programmatic objects are turned off or not supported
- Provide means to supply text or non-text equivalent insert
appropriately.
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: @@LRK: need help here.
- 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
Technique 6.5.1 [priority 2] Check that
a NOFRAMES
element exists within each FRAMESET
.
- Element:
FRAMESET
- Requirements:
- A valid
NOFRAMES
element should exist within each
FRAMESET
element
- The contents of the
NOFRAMES
element must allow the
user access to the site.
- 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
.
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
elements of the type 'animated gif'.
- Requirement: ask author to verify that flagged elements do not cause
flicker@@?
- Display flicker is distracting and may be dangerous to some users.
Please ensure this element does not cause the display to flicker.
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
- Element:
BLINK
- Requirement: Documents must not use the
BLINK
element.
- 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
- Element:
MARQUEE
.
- Requirement: Documents must not use the
MARQUEE
element.
- 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 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
- Requirement: auto-refresh is not allowed.
- 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. @@LRK added.
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
"
.
- Requirement: @@?
- 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.
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
.
- Requirement: @@? what can i say that is not the guideline or the
checkpoint text?
- 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
- If any programmatic elements are found in the document, provide a user
notification:
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
- Element:
IMG "ismap"
- Requirement: if only a server-side image map is used, text equivalents
for each link need to be provided. It is acceptable to provide both a
client-side and a server-side image map as long as the client-side is
marked up correctly. Refer to technique @@
- 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.
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: The following event handlers on any element:
onMouseDown()
onMouseUp()
onClick()
onMouseOver()
onMouseOut()
onMouseMove()
- Requirement: device dependent event handlers may be used, but only in
conjunction with logical event handlers.
- For scripts, specify logical event handlers rather than device-dependent
event handlers.
- "
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:
- A specified, logical tab order through active elements and objects
can be helpful to some users.
- Suspicious: no "
tabindex
" attribute
- Create a logical tabbing order through this page. Some people like to
skip over site navigation bars that appear at the top of each page in a
site. To allow someone to tab over it, set the tab order of the page such
that the navigation bar one of the last objects. Exception: if the tab
order is correct in the linearized version of the page.
@@LRK:: Issue: if the tabindex jumps around too much it could be confusing
to someone using magnification or a cognitive disability.
- Show the author a list of all of the active elements and their current
tab order. Allow them to change the order either by changing the number of
the tabindex or dragging and dropping an object to where it ought to
appear in the list.
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:
- Keyboard shortcuts to important active elements and objects can be
helpful for some users.
- Suspicious: no "
accesskey
" attribute
- Create short keys to important active elements on this page.
- 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:
A | AREA target="_blank"
A | AREA target="_new"
- Requirements:
A
and AREA elements should not have
"target
" attributes of "_blank
" or
"_new
".
A
and AREA
elements may have other
"target
" attribute values if there is another existing
window with the target name.
- 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
- Elements:
SCRIPT
- specifically calls to
window.open()
APPLET
- @@other embedded scripting languages?
- Requirement: @@?
- This script will open a new window that can be disorienting for some
users.
- Allow the user to remove the scripting call or to replace it with
??@@
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...