Please refer to the errata for this document, which may include some normative corrections.
See also translations .
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™
mobileOK™ Basic conformance and are
based on W3C Mobile Web Best Practices [Best Practices] . The details of how to claim
mobileOK conformance will be described separately. Providers of
content which passes the tests 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).
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 a Proposed Recommendation of
mobileOK Basic Tests 1.0. It reflects changes made as a result of
feedback received during the previous Candidate Recommendation
phase and of comments received during the following Last Call
review period. A disposition of comments report is available. The
entrance criteria to Proposed Recommendation are met and detailed
in the implementation report . The changes made to the document
since last publication as a Last Call Working Draft are editorial
clarifications with a view to removing potential ambiguities in the
way some of tests need to be conducted. See the accompanying
diff document to view the list of
changes made to this document since the previously published (10
June 2008) Last Call Working Draft. Main changes are: The text on
invalid certificates for URIs with the scheme HTTPS was adjusted
and moved to a separate section on HTTPS Handling of HTTP errors
was adjusted in the HTTP Response section The cases when an object
element should be treated as an Included Resource were clarified
The Object Element Processing rule was completed with a few
additional warnings Redundancy in the STYLE_SHEETS_USE test
was removed This document has been
produced developed by the
Mobile Web Best
Practices Working Group as part of the Mobile Web Initiative
.
This document is considered stable
by Please see the Mobile Web Best Practices Working Group. W3C Advisory Committee Representatives are
invited to submit their formal review per the instructions in the
Call for Review (see Group's
implementation report .A
complete list
of the Advisory Committee
questionnaire editorial
changes ). The W3C Membership and
other interested parties are invited to review since the previous version
of this document and is available.
Please send comments about this document to public-bpwg-comments@w3.org
(with public
archive ). The review period ends on 01
December 2008.
Publication as a Proposed Recommendation
does This document defines
machine-verifiable tests, based on the W3C Mobile Web Best
Practices [ Best Practices ].
Although content authors are not imply
endorsement expected to use this
document directly, participants of the Working Group expect tools
that implement the tests defined in this document to greatly
improve the authoring of content that addresses the browsing
experience of users on a broad range of devices.
This document has been reviewed by W3C
Members, by software developers, and by other W3C groups and
interested parties, and is endorsed by the Director as a W3C Membership. This Recommendation. It is a draft stable document
and may be updated, replaced
used as reference material or
obsoleted by other documents at any time.
It cited from another document. W3C's
role in making the Recommendation is inappropriate to cite this
document as other than work in progress. draw attention to the specification and to promote its
widespread deployment. This enhances the functionality and
interoperability of the Web.
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy . W3C maintains a public list of any 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 HTTPS
2.4.3 HTTP Request
2.4.4 HTTP Response
2.4.5 Meta http-equiv Elements
2.4.6 CSS Style
2.4.7 Included Resources
2.4.8 Linked Resources
2.4.9 Validity
2.4.10 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 [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.
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 .
mobileOK Basic tests are based on a limited subset of the Mobile Web Best Practices. Their outcome is machine-verifiable, hence claims of mobileOK Basic conformance are easy to check.
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 1.0] ) have been followed.
Some Best Practices, like TESTING , are advisable but do not meaningfully translate into concrete 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 Best Practices, and hence the tests, are not promoted as guidance for achieving the optimal user experience. The capabilities of many devices exceed those defined by the DDC. It will often be possible, and generally desirable, to provide an experience designed to take advantage of the extra capabilities.
Content providers should provide an experience that is mobileOK Basic conformant to ensure a basic level of interoperability. Providers are encouraged to provide enhanced experiences as well when these are appropriate to their application and devices that are accessing them.
The tests apply to a URI. Passing the tests means that when accessed as described in 2.4.3 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.
A standard mechanism will be defined that allows content providers to claim that a URI or group of URIs, such as a Web site, conforms to mobileOK Basic. It will be possible to make claims in a machine-processable form. It will also be possible to notify end users of the presence of the claim by means of a human-readable mark.
The details of the mechanism for claiming mobileOK conformance will be described separately.
Where terms are used with the meanings defined in [RFC 2119] they are highlighted in the text e.g. must .
mobileOK tests are only meaningful when the URI under test resolves to HTML content delivered over HTTP.
Individual tests may result in PASS or FAIL . PASS is required from all tests in order to claim mobileOK Basic conformance. In any test, PASS is achieved if and only if there are no FAIL s. No specific PASS outcome is defined for any test.
Tests may also generate a number of informative warn ings which do not affect whether a test has PASS ed or not. A warn ing may indicate that it could not be conclusively determined whether the content under test conforms to a Best Practice (and thus does not FAIL ), or may indicate that the content under test is close to violating a Best Practice.
mobileOK Basic does not prescribe the order in which tests are to be carried out as they may be executed independently. Some tests have been designed to assess aspects of the content that are disallowed by other tests; this is deliberate and is intended to allow testing environments to provide as much information as possible.
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.
Note:
Arbitrary root certificates (including self-signed certificates) should be regarded as trusted.
When resolving a URI, if the URI has the
scheme https :
If the certificate presented does not match the requested URI, FAIL
If the certificate has expired, or is not yet valid, warn
If certificate validation otherwise fails, FAIL
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 2.4.8 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 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 2.4.4 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 2.4.7 Included Resources and 2.4.8 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 .
Note:
Implementations must support basic and digest authentication.
Note:
Below, note that a 404 or 5xx response for the resource under test does not result in a FAIL in order to allow for the possibility of testing an application's error page.
Note:
If the test below results in a FAIL , do not proceed with further tests. Otherwise, the mobileOK Basic Tests should be applied to the content.
If an HTTP request does not result in a valid HTTP response (because of network-level error, DNS resolution error, or non-HTTP response), FAIL
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 (see 2.4.7 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 (see 2.4.7 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 2.4.8 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 2.4.8 Linked Resources ), continue with the test (see 3.10 LINK_TARGET_FORMAT ) and warn
Otherwise (i.e. for 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
Documents can include meta elements with an
http-equiv attribute; these are sometimes considered
substitutes for HTTP response headers.
mobileOK Basic test implementations must ignore values specified in such elements, aside from the following:
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
[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 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".
Some tests refer to Included Resources, which are resources external to the resource being tested and yet vital to rendering that resource and whose URI has the "http" or "https" scheme, when represented in an absolute form. Examples include image and style sheet resources.
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 are defined as those that are referenced 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 2.4.6 CSS Style
images included by background-image and
list-style-image properties in the CSS Style (see
2.4.6 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 2.4.6
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 as discussed under 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).
Linked Resources are resources linked to from the resource being tested (other than the resource itself), but which are not vital to rendering that resource whose URI begins with the "http" or "https" scheme when represented in an absolute form.
Linked resources are defined as those that are referenced by:
the href attribute of a (anchor)
elements.
the action attribute of form elements
whose method attribute is not present or is present
with value "get" (case-insensitive).
Note:
Forms with method attribute "POST"
(case-insensitive) are permissible in documents under test, but are
not checked by mobileOK Basic (posting might cause side effects
such as the addition of unwanted records to a database).
Note:
When submitting forms use default values where supplied, otherwise supply empty values.
Several tests refer to the validity of aspects of a resource. This section defines specifically what this means.
A resource is considered a valid CSS resource if it conforms to
the grammar defined in [CSS Level 1] , Appendix B . The
presence of at-rules, properties or values or combinations of
properties and values that are not specified in [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 [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 [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 section describes tests for mobileOK Basic. Tests are organized alphabetically by the Best Practice from which they derive. Where a test derives from more than one Best Practice it is placed according to the one that occurs first in dictionary order.
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 2.4.5 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 2.4.9 Validity ), FAIL
For each resource specified by 2.4.7 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 (see 2.4.7 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 2.4.9 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 2.4.9 Validity ), FAIL
Note:
inputmode is part of [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 [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 [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 2.4.4 HTTP Response ) to a running total.
For each unique Included Resource, as defined in 2.4.7 Included Resources :
Request the referenced resource
Add the number of HTTP requests that are
required to retrieve the resource (see 2.4.4 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 is an Included Resource (see
2.4.7 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 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
2.4.7 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 is an Included Resource (see
2.4.7 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 2.4.8 Linked Resources :
Request the resource
If the Content-Type header
value of the HTTP response is not one of the Internet media types
listed in the Accept header in 2.4.3 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 2.4.3 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 2.4.6 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
2.4.10 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.
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.
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
If the document contains a
frame , frameset or iframe
element, 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
For each img element that has
no object element ancestor (other than the context
node) in this context:
Treat this image as an Included Resource (and carry out appropriate tests).
For each object element that
has no object element ancestor (other than the context
node) in this context:
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 2.4.7 Included
Resources ), retrieve the referenced resource (ignoring
the type attribute)
If the Internet media type of the retrieved
resource, as indicated by its Content-Type HTTP header
does not match that stated in the type attribute,
warn
If the Internet media type indicated by the
Content-Type HTTP Header of the retrieved resource is
not "image/jpeg" or "image/gif", 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 2.4.4 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 ( 2.4.4 HTTP Response ).
For each unique Included Resource, as defined in 2.4.7 Included Resources :
Add the size of all the response bodies that
are required to retrieve the resource (see 2.4.4 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 2.4.7 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 2.4.10 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 2.4.6
CSS Style ) contains rules referencing the
position , display or float
properties, warn
This test looks for elements in the Text Extension module defined by [XHTML Modularization] , some of which are not supported in XHTML Basic [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 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 all styles are restricted to presentation
media types other than "handheld" or "all" by means of
@media at-rules, warn
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,
or if the value of a recognized CSS Level 1 property is
incompatible with the 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:
This appendix lists all Best Practices and indicates whether each has a corresponding test in mobileOK Basic.