Copyright © 2008 W3C ® ( MIT , ERCIM , Keio ), All Rights Reserved. W3C liability , trademark and document use rules apply.
This
document
defines
the
tests
that
provide
the
basis
for
making
a
claim
of
W3C®
mobileOK
Basic™
conformance
and
are
based
on
W3C
Mobile
Web
Best
Practices
[BestPractices]
[Best
Practices]
.
Content
The
details
of
how
to
claim
mobileOK
conformance
will
be
described
separately.
Providers
of
content
which
passes
the
tests
has
have
taken
some
steps
to
provide
a
functional
user
experience
for
users
of
basic
mobile
devices
whose
capabilities
at
least
match
those
of
the
Default
Delivery
Context
(DDC).
Claims
to
be
W3C
mobileOK
conformant
are
represented
using
Description
Resources
(see
[POWDER]
),
described
separately.
mobileOK
Basic
primarily
assesses
basic
usability,
efficiency
and
interoperability.
It
does
not
address
the
important
goal
of
assessing
whether
users
of
more
advanced
devices
enjoy
a
richer
user
experience
than
is
possible
using
the
DDC.
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
This is an Editors Draft of mobileOK Basic Tests 1.0. It reflects changes arising from implementation experience of a previous Candidate Recommendation. The Working Group does not expect substantive changes to the document from this point.
Publication as an Editors Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document has been produced by the Mobile Web Best Practices Working Group as part of the Mobile Web Initiative . Please send comments on this document to the Working Group's public email list public-bpwg@w3.org , a publicly archived mailing list .
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy . The W3C maintains a public list of patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy .
1
Introduction
1.1
Scope
1.1.1
Relationship
to
Best
Practices
1.1.2
Out
of
Scope
1.1.3
Beyond
mobileOK
1.2
Applicability
1.3
Claiming
mobileOK
conformance
2
Conformance
2.1
Use
of
Terms
must,
should
etc.
2.2
Validity
of
the
Tests
2.3
Testing
Outcomes
2.4
Conduct
of
Tests
2.4.1
Order
of
Tests
2.4.2
HTTP
Request
2.4.3
HTTP
Response
2.4.4
Meta
http-equiv
Elements
2.4.5
CSS
Style
2.4.6
Included
Resources
2.4.7
Linked
Resources
2.4.8
Validity
2.4.9
White
Space
3
mobileOK
Basic
Tests
3.1
AUTO_REFRESH
and
REDIRECTION
3.2
CACHING
3.3
CHARACTER_ENCODING_SUPPORT
and
CHARACTER_ENCODING_USE
3.4
CONTENT_FORMAT_SUPPORT
and
VALID_MARKUP
3.5
DEFAULT_INPUT_MODE
3.6
EXTERNAL_RESOURCES
3.7
GRAPHICS_FOR_SPACING
3.8
IMAGE_MAPS
3.9
IMAGES_RESIZING
and
IMAGES_SPECIFY_SIZE
3.10
LINK_TARGET_FORMAT
3.11
MEASURES
3.12
MINIMIZE
3.13
NO_FRAMES
3.14
NON-TEXT_ALTERNATIVES
3.15
OBJECTS_OR_SCRIPT
3.15.1
Object
Element
Processing
Rule
3.16
PAGE_SIZE_LIMIT
3.17
PAGE_TITLE
3.18
POP_UPS
3.19
PROVIDE_DEFAULTS
3.20
STYLE_SHEETS_SUPPORT
3.21
STYLE_SHEETS_USE
3.22
TABLES_ALTERNATIVES
3.23
TABLES_LAYOUT
3.24
TABLES_NESTED
A
Acknowledgments
(Non-Normative)
B
References
(Non-Normative)
C
Relationship
between
Best
Practices
and
mobileOK
Tests
(Non-Normative)
mobileOK
Basic
is
a
scheme
for
assessing
whether
Web
resources
(Web
content)
can
be
delivered
in
a
manner
that
is
conformant
with
Mobile
Web
Best
Practices
[BestPractices]
[Best
Practices]
to
a
simple
and
largely
hypothetical
mobile
user
agent,
the
Default
Delivery
Context
.
This document describes W3C mobileOK Basic tests for delivered content, and describes how to emulate the DDC when requesting that content.
Claims
to
be
W3C
mobileOK
Basic
conformant
are
represented
using
Description
Resources
(see
[POWDER]
)
described
separately.
The
intention
of
mobileOK
is
to
help
catalyze
development
of
Web
content
that
provides
a
functional
user
experience
in
a
mobile
context.
It
is
not
a
test
for
browsers,
user
agents
or
mobile
devices,
and
is
not
intended
to
imply
anything
about
the
way
these
should
behave.
mobileOK does not imply endorsement or suitability of content. For example, it must not be assumed that a claim that a resource is mobileOK conformant implies that it is of higher informational value, is more reliable, more trustworthy or is more appropriate for children than any other resource .
Content passing the tests demonstrates that the content provider has taken basic steps to provide a functional experience for mobile users.
mobileOK
Basic
conformance
should
be
considered
only
a
first
step
towards
building
a
harmonized
experience
for
mobile
users.
Conformance
merely
demonstrates
that
a
basic
experience
is
available,
interoperable
with
a
large
number
of
mobile
devices.
mobileOK
Basic
conformance
says
nothing
about
richer,
more
sophisticated,
experiences
that
may
be
available,
nor
does
it
say
anything
about
whether
other
guidelines
for
development
of
Web
content
(such
as
[WCAG]
[WCAG
1.0]
)
have
been
followed.
Some
Best
Practices,
like
TESTING
,
are
advisable
but
do
not
meaningfully
translate
into
concrete
tests,
whether
their
outcome
is
machine-
or
human-verifiable.
tests.
The tests assess whether the content can be provided in a way that achieves basic usability, efficiency, and interoperability with mobile devices. The tests should not be understood to assess thoroughly whether the content has been well-designed for mobile devices.
The tests apply to a URI. Passing the tests means that when accessed as described in 2.4.2 HTTP Request , resolving a URI will result in mobileOK Basic conformant content that is delivered in a mobileOK Basic conformant manner.
That is, the tests do not apply solely to content or document instances. Many Best Practices relate not just to the document (e.g. VALID_MARKUP ), but to how it is delivered to a mobile device (e.g. CACHING ).
mobileOK Basic says nothing about what may be delivered to non-mobile devices.
Where terms are used with the meanings defined in [RFC 2119] they are highlighted in the text e.g. must .
For
example
the
test
for
3.21
STYLE_SHEETS_USE
points
out
that
style
sheets
should
be
used
in
preference
to
markup
elements
such
as
center
,
even
though
the
center
element
is
also
disallowed
by
the
test
for
3.4
CONTENT_FORMAT_SUPPORT
and
VALID_MARKUP
.
Creators of implementations of the tests described in this document are encouraged to provide as much information as possible to users of their implementations. Where possible they should not stop on FAIL and specifically they should :
Provide information about the cause of warning or failure (each warn and FAIL is individually identified);
Continue individual tests as far as is possible;
Carry out as many tests as is reasonable.
The following HTTP request headers inform the server that it should deliver content that is compatible with the Default Delivery Context .
Use
the
HTTP
GET
method
when
making
requests,
except
for
3.10
LINK_TARGET_FORMAT
where
the
HEAD
method
may
be
used
(See
2.4.7
Linked
Resources
for
a
discussion
of
the
POST
method).
Include
a
User-Agent
header
which
starts
exactly
as
follows
(indicating
the
Default
Delivery
Context,
and
which
may
be
extended
in
accordance
with
[RFC
2616]
Section
14.43,
User-Agent
Header
)
:
User-Agent: W3C-mobileOK/DDC-1.0 (see http://www.w3.org/2006/07/mobileok-ddc)
Include
an
Accept
header
indicating
that
Internet
media
types
understood
by
the
default
delivery
context
Default
Delivery
Context
are
accepted
by
sending
exactly
this
header:
Accept: application/xhtml+xml,text/html;q=0.1,application/vnd.wap.xhtml+xml;q=0.1,text/css,image/jpeg,image/gif
Include
an
Accept-Charset
header
indicating
that
only
UTF-8
is
accepted
by
sending
exactly
this
header:
Accept-Charset: UTF-8
Do not include cookie related headers.
Include authentication information if required (see 2.4.3 HTTP Response ). Once authentication information has been included in a request, subsequent requests for the same realm must include authentication information as described in Section 2 and under "domain" in Section 3.2.1 of [RFC 2617] .
Implementations
must
support
URIs
with
both
http
and
https
scheme
components.
Note:
As
noted
under
2.4.6
Included
Resources
and
2.4.7
Linked
Resources
the
URIs
that
are
relevant
to
mobileOK
are
those
that,
when
represented
in
an
absolute
form,
have
either
the
http
or
the
https
scheme.
Requests
should
not
be
made
for
URIs
with
schemes
other
than
http
and
https
.
If
the
response
is
an
HTTPS
response:
results
from
a
request
with
a
URI
with
the
scheme
https
:
If the certificate is invalid, FAIL
If the certificate has expired, warn
If the HTTP status indicates redirection (status code 3xx):
Do not carry out tests on the response
If
the
response
relates
to
a
request
for
the
resource
under
test,
or
any
of
its
included
resources
Included
Resources
(see
2.4.6
Included
Resources
):
Include the size of the response in the "total size" as described under 3.16 PAGE_SIZE_LIMIT
Include this response under the count as described under 3.6 EXTERNAL_RESOURCES
If
there
is
no
HTTP
Location
header,
FAIL
.
If
the
URI
identified
by
the
HTTP
Location
header
is
a
relative
URI,
create
an
absolute
URI
by
combining
the
value
of
the
Location
header
with
the
absolute
URI
of
the
request
to
which
this
is
a
response,
warn
If
the
resulting
URI
is
not
a
URI
with
the
scheme
http
or
https
,
FAIL
.
Re-request the resource using the URI formulated above.
If the HTTP status indicates that authentication is required (e.g. status code 401):
If
the
response
relates
to
a
request
for
the
resource
under
test,
or
any
of
its
included
resources
Included
Resources
(see
2.4.6
Included
Resources
):
If authentication information was supplied in the HTTP request (i.e. authentication failed) or if no authentication information is available, FAIL
Carry out tests on the response
Include the size of the response in the "total size" as described under 3.16 PAGE_SIZE_LIMIT
Include this response under the count as described under 3.6 EXTERNAL_RESOURCES
Re-request the resource using authentication information
If the response relates to a request for a linked resource (see 2.4.7 Linked Resources ):
Continue with the test (see 3.10 LINK_TARGET_FORMAT , i.e. do not re-request the resource with authentication information), warn
If the HTTP status code is 404 or 5xx
If the response relates to a request for the resource under test, continue with tests on the response and warn
If the response relates to a request for a linked resource (see 2.4.7 Linked Resources ), continue with the test (see 3.10 LINK_TARGET_FORMAT ) and warn
Otherwise
(i.e.
for
included
resources),
Included
Resources),
FAIL
If the HTTP status represents failure (4xx), other than 404, a request for authentication (e.g. 401) or a 406 when carrying out the 3.15.1 Object Element Processing Rule , FAIL
The
Refresh
header
as
specified
in
3.1
AUTO_REFRESH
and
REDIRECTION
The
Content-Type
header
as
specified
in
3.3
CHARACTER_ENCODING_SUPPORT
and
CHARACTER_ENCODING_USE
The
Cache-Control
header
as
specified
in
3.2
CACHING
Check for consistency with HTTP headers, as follows:
For
each
meta
element
with
an
http-equiv
attribute:
If a matching HTTP response header does not exist, warn
If
a
matching
HTTP
response
header
exists
but
its
value
differs
from
the
content
attribute
value,
warn
Some tests refer to "CSS Style" information. Assemble the CSS Style by using the contents of:
the
style
attribute
of
any
element
(use
of
the
style
attribute
is
deprecated
in
XHTML
Basic
1.1
[XHTMLBasic11]
[XHTML
Basic
1.1]
)
style
elements
whose
type
attribute
is
"text/css",
and
whose
media
attribute
is
either
not
present
or
is
present
and
contains
values
"all"
or
"handheld"
(case-insensitive).
resources
linked
via
link
elements
and
xml-stylesheet
processing
instructions,
where:
the
rel
attribute
contains
"stylesheet"
but
not
"alternate"
(case-insensitive)
the
charset
attribute
is
either
not
present
or
is
present
with
value
"UTF-8"
(case-insensitive)
the
type
attribute
is
either
not
present
or
is
present
with
value
"text/css"
the
media
attribute
is
either
not
present
or
is
present
and
contains
value
"all"
or
"handheld"
(case-insensitive).
Note:
In
the
case
of
xml-stylesheet
processing
instructions,
attribute
in
this
section
refers
to
pseudo-attribute
.
resources
linked
by
CSS
@import
at-rules
whose
presentation
media
list
is
either
not
present
or
is
present
and
contains
values
the
value
"all"
or
"handheld"
In the course of assembling the CSS Style use only those CSS rulesets that are not restricted as to their presentation media type or whose presentation media type list contains "handheld" or "all".
When retrieving resources, caching directives should be observed. Multiple references to cached resources are counted only once in regard of page weight (see 3.16 PAGE_SIZE_LIMIT ) and resource count (see 3.6 EXTERNAL_RESOURCES ).
Included
resources
Resources
are
defined
as
those
that
are
referenced
by:
by
the
following:
the
src
attribute
of
img
elements
the
data
attribute
of
object
elements
(see
notes
below)
the
href
attribute
of
link
elements
and
xml-stylesheet
processing
instructions
as
defined
in
2.4.5
CSS
Style
images
included
by
background-image
and
list-style-image
properties
in
the
CSS
Style
(
(see
2.4.5
CSS
Style
)
@import
directives
in
the
CSS
Style
-
providing
they
are
unqualified
as
to
presentation
media
type
or
qualified
by
presentation
media
type
"handheld"
or
"all"
(case-insensitive)
as
defined
in
2.4.5
CSS
Style
Note:
In
some
circumstances
object
elements
may
act
as
synonyms
for
other
elements
such
as
img
and
iframe
.
In
these
cases
it
is
noted
in
the
relevant
section
when
to
regard
object
elements
as
equivalents
for
other
elements.
Note:
Resources
that
are
retrieved
as
references
from
object
elements
and
whose
Content-Type
HTTP
header
is
not
set
to
"image/jpeg"
or
"image/gif"
are
not
considered
to
be
included
resources
(see
Included
Resources
as
discussed
under
3.15
OBJECTS_OR_SCRIPT
3.15.1
Object
Element
Processing
Rule
).
(i.e.
objects
that
are
"tasted"
to
determine
their
Internet
content
type
but
are
then
discarded
are
not
Included
Resources).
Their
treatment,
as
regards
3.16
PAGE_SIZE_LIMIT
and
3.6
EXTERNAL_RESOURCES
,
is
described
in
the
relevant
section.
Note:
Resources
referenced
by
descendants
of
an
object
element
that
itself
refers
to
an
Included
Resource
are
not
considered
to
be
Included
Resources
as
discussed
under
3.15.1
Object
Element
Processing
Rule
(i.e.
any
img
or
object
element
which
occurs
in
the
fall-back
of
an
acceptable
object
element
is
not
an
Included
Resource).
A
resource
is
considered
a
valid
CSS
resource
if
it
conforms
to
the
grammar
defined
in
[CSS]
[CSS
Level
1]
,
Appendix
B
(see
note
below)
,
except
that
@media
at-rules,
which
are
not
part
of
the
grammar,
are
allowed
and
are
not
considered
invalid.
.
The
presence
of
at-rules,
properties
or
values
or
combinations
of
properties
and
values
that
are
not
specified
in
[CSS]
[CSS
Level
1]
does
not
constitute
a
validity
failure
for
CSS.
See
3.21
STYLE_SHEETS_USE
for
treatment
of
such
values.
In
addition,
the
@media
at-rule
and
the
presentation
media
list
for
the
@import
at-rule
are
taken
into
account
when
evaluating
CSS.
An image is a valid GIF image if it conforms to the grammar defined in section 25 of the [GIF] specification.
An image is a valid JPEG image if it follows the format defined in Annex B of the [JPEG] specification
A
resource
is
considered
to
be
valid
UTF-8
if
its
bytes
represent
the
valid
UTF-8
encoding
of
some
string,
as
defined
in
[UTF-8]
[RFC
3629]
,
section
4
Several
tests
refer
to
white
space.
White
space
has
the
same
definition
in
this
document
as
in
XML.
For
XML
1.0
[XML10]
[XML
1.0]
it
is
defined
in
http://www.w3.org/TR/REC-xml/#sec-common-syn
as
being:
S
::=
(#x20
|
#x9
|
#xD
|
#xA)+
i.e.
the
characters
SP,
TAB,
CR
and
LF.
This test does not determine whether the user is able to opt out of refresh.
If
a
meta
element
is
present
with
http-equiv
attribute
value
of
"refresh",
If
the
URI
specified
as
part
of
the
content
attribute
is
not
the
current
resource's
URI,
FAIL
Else, warn
If
a
Refresh
HTTP
header
is
present,
If the URI specified in the header value is not the current resource's URI, FAIL
Else, warn
The purpose of the test is to alert providers to the fact that their content may not be cached, if it would be beneficial to do so.
Note:
Where
both
a
meta
element
with
http-equiv
attribute
and
the
corresponding
HTTP
header
are
found,
the
value
of
the
HTTP
header
must
be
used
-
see
also
note
under
2.4.4
Meta
http-equiv
Elements
.
If
the
HTTP
response
contains
neither
an
Expires
nor
Cache-Control
header
If
no
meta
http-equiv
element
is
present,
referring
to
those
headers,
FAIL
Continue
the
test
using
the
value
from
the
meta
content
attribute
as
though
it
were
specified
in
the
appropriate
header,
warn
If
a
Cache-Control
HTTP
header
is
present
and
contains
value
"no-cache",
or
contains
value
"max-age=0",
warn
If
a
Pragma
HTTP
header
is
present
and
contains
value
"no-cache",
warn
If
an
Expires
and
Date
HTTP
header
are
present,
and
the
Expires
header
specifies
a
date
which
is
not
later
than
what
the
Date
header
specifies,
warn
If any cache related header contains an invalid value, warn
If
the
HTTP
response
contains
a
Last-Modified
header,
Request
the
same
URI
again,
adding
an
If-Modified-Since
request
header
whose
value
matches
that
of
the
Last-Modified
response
header
If
the
HTTP
response
contains
a
Last-Modified
header
and
its
value
is
again
the
same,
and
the
HTTP
response
status
is
not
304
(Not
Modified),
warn
If
the
HTTP
response
contains
an
ETag
header,
Request
the
same
URI
again,
adding
an
If-None-Match
request
header
whose
value
matches
that
of
the
ETag
response
header
If
the
HTTP
response
contains
an
ETag
header
and
its
value
is
again
the
same,
and
the
HTTP
response
status
is
not
304
(Not
Modified),
warn
The DDC is defined to support only UTF-8 encoding, and hence this test fails if a resource is not encoded in UTF-8. The test does not require that resource always be encoded in UTF-8; the test merely checks that the resource is available in UTF-8 encoding, if requested. Resources may be represented using other encodings where appropriate. This test verifies that a DDC-like device which only accepts UTF-8 encoding may access the resource in UTF-8 encoding.
This test requires that character encoding is explicitly specified and recognizes the following methods of specification:
HTTP
Content-Type
header
application/xhtml+xml ; charset=UTF-8
XML declaration
<?xml version="1.0" encoding="UTF-8" ?>
meta
element
that
is
the
first
child
of
the
document's
head
element,
and
whose
http-equiv
attribute
is
"Content-Type",
and
whose
content
attribute
specifies
a
character
encoding
... <head> <meta http-equiv="Content-Type" content="application/xhtml+xml ; charset=UTF-8 "/> ...
If
the
HTTP
Content-Type
header
specifies
a
character
encoding
other
than
UTF-8,
FAIL
If
the
HTTP
Content-Type
header
does
not
specify
a
character
encoding:
If there is no XML declaration, or UTF-8 character encoding is not specified in the XML declaration, FAIL
If
the
HTTP
Content-Type
header
specifies
an
Internet
media
type
starting
with
"text/":
If
there
is
no
meta
element
with
http-equiv
attribute
that
specifies
UTF-8
character
encoding,
FAIL
If character encoding is specified in more than one way, and not all values are the same, FAIL
If the document is not valid UTF-8 (see 2.4.8 Validity ), FAIL
For each resource specified by 2.4.6 Included Resources :
Request the resource
If
the
HTTP
Content-Type
header
value
of
the
response
starts
with
"text/"
but
does
not
specify
UTF-8
character
encoding,
warn
Note:
In the following, an "html document" is a document that has "html" as its root element.
Note:
In
the
following,
"regardless
of
its
stated
DOCTYPE
"
means
that
when
assessing
validity
against
the
XHTML
Basic
1.1
and
XHTML
MP
1.2
DTDs
this
may
be
carried
out
by
inserting
a
DOCTYPE
if
none
is
present,
or
by
replacing
the
given
DOCTYPE
with
the
appropriate
DOCTYPE
for
the
DTD
under
test.
Note:
In the following, "a known XHTML version" means XHTML Basic 1.0, XHTML Basic 1.1, XHTML-MP 1.0, XHTML-MP 1.1 or XHTML-MP 1.2.
If
the
document's
Internet
media
type,
as
specified
in
the
HTTP
response
Content-Type
header,
is
not
"application/xhtml+xml",
"application/vnd.wap.xhtml+xml",
or
"text/html",
FAIL
If the document's Internet media type is "text/html" or "application/vnd.wap.xhtml+xml", warn
If
the
document
does
not
contain
a
DOCTYPE
declaration,
FAIL
If the document is not an HTML document , FAIL
If
the
DOCTYPE
is
not
an
XML
DOCTYPE
,
warn
If
the
document
is
an
HTML
document
and
it
has
an
XML
DOCTYPE
:
If
the
document
does
not
declare
the
html
namespace
on
its
html
root
element,
FAIL
If
the
DOCTYPE
refers
to
a
known
XHTML
version
,
validate
against
that
DOCTYPE
and
if
invalid,
warn
Otherwise
(if
the
DOCTYPE
is
not
known),
warn
If ( regardless of its stated DOCTYPE ) the document does not validate against the XHTML Basic 1.1 DTD:
If ( regardless of its stated DOCTYPE ) it does not validate against the XHTML-MP 1.2 DTD, FAIL
For
each
included
resource
Included
Resource
(see
2.4.6
Included
Resources
):
If the response specifies an Internet media type that is not "text/css", "image/jpeg" or "image/gif", FAIL
If an image is required (see also 3.15 OBJECTS_OR_SCRIPT ) and the response specifies an Internet media type that is not "image/jpeg" or "image/gif", FAIL
If the Internet media type is "image/gif" or "image/jpeg", and the resource is not valid (see 2.4.8 Validity ), FAIL
If a style sheet is required and the response specifies an Internet media type that is not "text/css", FAIL
If the Internet media type is "text/css" and the content is not valid CSS (see 2.4.8 Validity ), FAIL
Note:
inputmode
is
part
of
[XHTMLBasic11]
[XHTML
Basic
1.1]
.
For
each
input
element
with
attribute
type
whose
value
is
"text"
or
"password"
or
whose
type
attribute
is
missing:
If
the
element's
inputmode
attribute
is
invalid
according
to
Section
5.2
User
Agent
Behavior
of
XHTML
Basic
1.1
[XHTMLBasic11]
[XHTML
Basic
1.1]
,
FAIL
If
the
element's
value
attribute
is
missing
or
empty,
and
an
inputmode
attribute
is
not
present,
warn
For
each
textarea
element:
If
the
element's
inputmode
attribute
is
invalid
according
to
Section
5.2
User
Agent
Behavior
of
XHTML
Basic
1.1
[XHTMLBasic11]
[XHTML
Basic
1.1]
,
FAIL
If
the
element
is
empty
and
an
inputmode
attribute
is
not
present,
warn
Retrieve the resource under test, and add the number of retrievals required to obtain the resource (see 2.4.3 HTTP Response ) to a running total.
For
each
unique
included
resource,
Included
Resource,
as
defined
in
2.4.6
Included
Resources
:
Request the referenced resource
Add
the
number
of
HTTP
requests
that
are
required
to
retrieve
the
resource
(see
2.4.3
HTTP
Response
)
to
the
running
total.
Include
in
the
count
only
those
objects
retrieved
under
the
3.15.1
Object
Element
Processing
Rule
whose
type
attribute
is
not
specified,
and
those
whose
content
type
is
either
"image/jpeg"
or
"image/gif"
irrespective
of
whether
the
type
attribute
is
specified.
If the total exceeds 10, warn
If this total exceeds 20, FAIL
The intent of this Best Practice is to avoid using transparent images for spacing. However, small transparent images are often used in e-commerce sites for user tracking purposes. The practice is common enough, and possibly vital enough to the business interests of mobile sites, that it is undesirable to fail sites that use such small transparent images. Therefore this machine-testable test merely warn s about the presence of small (at most 2x2) transparent images and FAIL s larger ones. It is believed that few if any sites would use transparent images of any significant size for tracking.
For
each
img
element
and
object
element
which
when
retrieved
has
is
an
Internet
media
type
that
starts
with
"image/"
:
Included
Resource
(see
2.4.6
Included
Resources
):
If all pixels are transparent,
If image height and width are both less than or equal to 2 pixels, warn
If either dimension exceeds 2 pixels, FAIL
If
more
than
one
image
with
all
transparent
pixels
was
encountered,
is
present,
warn
If
an
input
element
with
type
attribute
set
to
"image"
is
present,
FAIL
For
each
img
element
and
object
element
:
which
is
an
Included
Resource
(see
2.4.6
Included
Resources
):
If
a
usemap
attribute
is
present,
FAIL
If
an
ismap
attribute
is
present,
FAIL
Note:
The
height
and
width
HTML
attributes
specify
pixels
when
they
are
used
as
a
number.
No
unit
is
specified.
For
each
img
element
and
object
element
which
when
retrieved
has
is
an
Internet
media
type
that
starts
with
"image/":
Included
Resource
(see
2.4.6
Included
Resources
):
If
the
height
or
width
attribute
are
missing,
FAIL
If
the
height
or
width
attribute
do
not
specify
a
size
in
pixels,
FAIL
If the value specified by either the height or width attribute is greater than the corresponding dimension of the image, warn
If the value specified by either the height or width attribute is less than the corresponding dimension of the image, FAIL
Note:
404 and 5xx HTTP status do not result in failure when conducting this test.
Note:
The document body of linked resources is not examined.
For each linked resource, as defined in 2.4.7 Linked Resources :
Request the resource
If
the
Content-Type
header
value
of
the
HTTP
response
is
not
one
of
the
Internet
Media
Types
media
types
listed
in
the
Accept
header
in
2.4.2
HTTP
Request
,
warn
If
the
Content-Type
header
value
of
the
HTTP
response
does
not
specify
a
charset
parameter,
or
does
but
it
is
not
consistent
with
the
value
of
the
Accept-Charset
header
in
2.4.2
HTTP
Request
,
warn
For each document internal reference (links in the document under test that refer to the document itself):
If there is no target for the reference or it is invalid (e.g. '#'), warn
Note:
The
intrinsic
size
of
images
must
be
specified
as
attributes
of
the
img
element
and
not
as
CSS
properties
(see
3.9
IMAGES_RESIZING
and
IMAGES_SPECIFY_SIZE
)
Note:
Only CSS Level 1 properties are considered in this test.
For
each
CSS
Level
1
property
in
the
CSS
Style
(
(see
2.4.5
CSS
Style
)
whose
value
is
a
numeric
measure
of
length
stated
together
with
a
unit:
If the value is non-zero and the unit is not "em" or "ex" (and the value is not a percentage), and the property is not a margin, border or padding box property, FAIL
Note:
Extraneous white space characters in script and in CSS are not considered in this test. Such an extension may be considered in a future revision of this specification.
Count
number
of
white
space
characters
(see
2.4.9
White
Space
)
in
a
sequence
of
more
than
one
white
space
character
(not
counting
the
first),
which
exist
outside
of
a
pre
,
style
,
script
element,
or
XML
comment
comment.
Add to this count the number of characters comprising XML comments. This total is the number of extraneous characters in the document.
Count
total
number
of
characters
in
document
document.
If the number of extraneous characters exceeds 10% of the count of characters in the document, warn
If the number of extraneous characters exceeds 25% of the count of characters in the document, FAIL
This test does not determine whether the alternative text is meaningful.
Note:
An
empty
alt
attribute
is
acceptable
and
signifies
that
there
is
no
meaningful
textual
alternative,
for
example
for
images
that
are
purely
decorative.
For
each
img
element:
If
an
alt
attribute
is
not
present
or
contains
only
white
space
,
FAIL
This test does not determine whether the document is still usable without the objects or scripts.
If
a
script
element
is
present,
warn
If
any
element
has
an
"intrinsic
event"
attribute
(currently
onload
,
onunload
,
onclick
,
ondblclick
,
onmousedown
,
onmouseup
,
onmouseover
,
onmousemove
,
onmouseout
,
onfocus
,
onblur
,
onkeypress
,
onkeydown
,
onkeyup
,
onsubmit
,
onreset
,
onselect
,
onchange
),
warn
For
each
a
and
link
element:
If
the
value
of
the
href
attribute
begins
with
the
"javascript:"
scheme,
FAIL
If
an
applet
element
is
present,
FAIL
Set the context to the root element and apply the Object Element Processing Rule
Treat this image as an Included Resource (and carry out appropriate tests).
If
the
object
element
is
empty,
warn
If
the
content
of
the
object
element
consists
only
of
white
space,
FAIL
If
there
is
no
type
attribute,
warn
If
it
is
not
already
cached
(see
2.4.6
Included
Resources
),
retrieve
the
referenced
resource
(ignoring
the
type
attribute)
If
the
Internet
media
type
of
the
retrieved
resource,
as
indicated
by
the
its
Content-Type
HTTP
Header
of
the
retrieved
resource
is
not
"image/jpeg"
or
"image/gif",
warn
If
the
content
type
of
the
retrieved
resource
header
does
not
match
that
stated
in
the
type
attribute,
warn
For
each
img
element
that
has
no
object
element
ancestor
in
this
context:
If
the
content
Internet
media
type
of
indicated
by
the
img
Content-Type
element
HTTP
Header
of
the
retrieved
resource
is
not
"image/jpeg"
or
"image/gif",
FAIL
warn
Reapply
this
rule
using
the
current
object
element
as
the
context
Otherwise (the object is an acceptable image):
Treat
this
object
as
an
Included
Resource
(and
carry
out
appropriate
tests),
ignore
img
and
object
elements
that
are
descendants
of
the
current
object
element.
Note:
A
warning
is
issued
when
the
Internet
media
type
indicated
by
the
type
attribute
is
not
compatible
with
the
Default
Delivery
Context
because
some
user
agents
do
not
take
into
account
the
type
attribute
of
object
elements
and
this
may
cause
the
user
agent
to
retrieve
large
incompatible
objects
with
consequences
to
performance
and
cost.
Note:
An HTTP 406 status on retrieval of a resource referenced by an object element does not constitute a FAIL.
Retrieve the document under test, if its size (excluding any redirections discussed under 2.4.3 HTTP Response ) exceeds 10 kilobytes, FAIL
Add to a running total (total size) the size of all the HTTP response bodies that are required to retrieve the document under test ( 2.4.3 HTTP Response ).
For
each
unique
included
resource,
Included
Resource,
as
defined
in
2.4.6
Included
Resources
:
Add
the
size
of
all
the
response
bodies
that
are
required
to
retrieve
the
resource
(see
2.4.3
HTTP
Response
)
to
the
running
total.
Include
in
the
total
only
those
objects
retrieved
under
the
3.15.1
Object
Element
Processing
Rule
whose
type
attribute
is
not
specified,
and
those
whose
Internet
media
type
as
indicated
by
the
Content-Type
HTTP
header
is
either
"image/jpeg"
or
"image/gif"
irrespective
of
whether
the
type
attribute
is
specified.
If the total exceeds 20 kilobytes, FAIL
Note:
In the case of resources that are referenced more than once in the document under test, and where, as discussed under 2.4.6 Included Resources , they are cached, it is the initial retrieval of that resource (as determined by the first reference in document order) that counts towards the total.
Note:
Where the 3.15.1 Object Element Processing Rule yields a resource that is found to be cached, objects that must be assessed in the course of yielding the cached resource count towards the total.
This test does not determine whether the title is meaningful.
If
a
title
element
is
not
present
in
the
head
element,
or
is
empty,
or
contains
only
white
space
(see
2.4.9
White
Space
),
FAIL
For
each
a
,
link
,
form
,
and
base
element:
If
a
target
attribute
is
present,
If its value is not one of "_self", "_parent", or "_top", FAIL
For
each
radio
button
group
within
a
form
element
(
input
elements
with
type
"radio"
that
share
the
same
name
attribute
value):
Check
that
exactly
one
input
element
within
this
group
has
its
checked
attribute
set
to
"checked",
and
if
this
is
not
the
case,
warn
For
each
select
element:
If
there
is
no
nested
option
element
whose
selected
attribute
is
set
to
"selected",
warn
If
there
is
more
than
one
option
element
whose
selected
attribute
is
set
to
"selected",
and
the
multiple
attribute
is
not
set
to
"multiple",
warn
If
the
CSS
Style
(
(see
2.4.5
CSS
Style
)
contains
rules
referencing
the
position
,
display
or
float
properties,
warn
This
test
looks
for
elements
in
the
Text
Extension
module
defined
by
[XHTMLModularization]
[XHTML
Modularization]
,
some
of
which
are
not
supported
in
XHTML
Basic
[XHTMLBasic11]
[XHTML
Basic
1.1]
.
It
also
looks
for
commonly-used
elements
and
attributes
that
were
deprecated
in
HTML
4,
and
are
not
supported,
or
are
deprecated,
in
XHTML
Basic.
Note:
This
test
does
not
require
that
any
CSS
styles
be
Style
is
used,
since
in
some
cases,
no
presentation
information
is
required
at
all
(for
example,
a
simple
page
of
text).
If
the
document
contains
any
basefont
,
bdo
,
center
,
del
,
dir
,
font
,
ins
,
menu
,
s
,
strike
or
u
elements,
FAIL
If
the
document
contains
any
b
,
big
,
i
,
small
,
sub
,
sup
or
tt
elements,
warn
If
any
element
has
a
style
attribute,
warn
If
there
is
CSS
Style
(
2.4.5
CSS
Style
)
If
all
styles
are
restricted
to
presentation
media
types
other
than
"handheld"
or
"all"
by
means
of
@media
at-rules,
warn
at-
rules,
If
the
CSS
Style
contains
at-rules
(other
than
the
@media
at-rule,
and
the
presentation
media
type
list
of
the
@import
at-rule),
properties,
or
values
that
are
not
recognized
as
being
specified
in
CSS
Level
1,
warn
If
or
if
the
CSS
Style
contains
a
property
with
a
value
that
is
inappropriate
to
it,
warn
If
the
CSS
Style
contains
of
a
recognized
CSS
Level
1
property
with
a
value
that
requires
a
unit
or
a
percentage:
If
the
unit
(or
percentage)
is
not
present,
warn
If
the
unit
(or
percentage)
is
inappropriate
to
incompatible
with
the
value,
property,
warn
If
a
table
element
exists,
warn
This test does not catch all cases where tables are used for layout purposes.
For
each
table
element:
If
it
contains
at
most
one
tr
element,
FAIL
If
no
tr
element
contains
more
than
one
td
element,
FAIL
For
each
nested
td
element:
If the element contains only an image (or equivalent object) whose actual dimensions are 2x2 or less, FAIL
For
each
table
element:
If
it
contains
a
table
element,
FAIL
The editors would like to thank members of the BPWG for contributions of various kinds.
The editors acknowledge significant written contributions from: