Features listed in this section will trigger warnings in conformance checkers.
Authors should not specify an http-equiv
attribute in the
Content
Language state on a meta
element. The lang
attribute should be used instead.
Authors should not specify a border
attribute on an
img
element. If the attribute is present, its value
must be the string "0
". CSS should be used
instead.
Authors should not specify a language
attribute on a
script
element. If the attribute is present, its value
must be an ASCII case-insensitive match for the string
"JavaScript
" and either the type
attribute must be omitted or
its value must be an ASCII case-insensitive match for
the string "text/javascript
". The attribute
should be entirely omitted instead (with the value "JavaScript
", it has no effect), or replaced with use
of the type
attribute.
Authors should not specify the name
attribute on a
elements. If the attribute is present, its value must not be the
empty string and must neither be equal to the value of any of the
IDs in the element's home
subtree other than the element's own ID, if any, nor be equal to the value of
any of the other name
attributes on
a
elements in the element's home
subtree. If this attribute is present and the element has an
ID, then the attribute's value must
be equal to the element's ID. In
earlier versions of the language, this attribute was intended as a
way to specify possible targets for fragment identifiers in URLs. The id
attribute should be used instead.
In the HTML syntax, specifying a DOCTYPE that is an obsolete permitted DOCTYPE will also trigger a warning.
The summary
attribute, defined in the table
section, will also
trigger a warning.
Elements in the following list are entirely obsolete, and must not be used by authors:
applet
acronym
Use abbr
instead.
bgsound
Use audio
instead.
dir
Use ul
instead.
frame
frameset
noframes
Either use iframe
and CSS instead, or use server-side includes to generate complete pages with the various invariant parts merged in.
isindex
Use an explicit form
and text field combination instead.
listing
xmp
nextid
Use GUIDs instead.
noembed
plaintext
Use the "text/plain
" MIME type instead.
rb
Providing the ruby base directly inside the ruby
element is sufficient; the rb
element is unnecessary. Omit it altogether.
strike
Use del
instead if the element is marking an edit, otherwise use s
instead.
basefont
big
blink
center
font
marquee
multicol
nobr
spacer
tt
u
Use appropriate elements and/or CSS instead.
Where the tt
element would have been used for
marking up keyboard input, consider the kbd
element;
for variables, consider the var
element; for computer
code, consider the code
element; and for computer
output, consider the samp
element.
Similarly, if the u
element is being used to
indicate emphasis, consider using the em
element; if
it is being used for marking up keywords, consider the
b
element; and if it is being used for highlighting
text for reference purposes, consider the mark
element.
See also the text-level semantics usage summary for more suggestions with examples.
The following attributes are obsolete (though the elements are still part of the language), and must not be used by authors:
charset
on a
elementscharset
on link
elementsUse an HTTP Content-Type header on the linked resource instead.
coords
on a
elementsshape
on a
elementsmethods
on a
elementsmethods
on link
elementsUse the HTTP OPTIONS feature instead.
name
on a
elements (except as noted in the previous section)name
on embed
elementsname
on img
elementsname
on option
elementsUse the id
attribute instead.
rev
on a
elementsrev
on link
elementsUse the rel
attribute instead, with an opposite term. (For example, instead of
rev="made"
, use rel="author"
.)
urn
on a
elementsurn
on link
elementsSpecify the preferred persistent identifier using the href
attribute instead.
nohref
on area
elementsOmitting the href
attribute is sufficient; the nohref
attribute is
unnecessary. Omit it altogether.
profile
on head
elementsWhen used for declaring which meta
terms are
used in the document, unnecessary; omit it altogether, and register the names.
When used for triggering specific user agent behaviors: use
a link
element instead.
version
on html
elementsUnnecessary. Omit it altogether.
usemap
on input
elementslongdesc
on iframe
elementslongdesc
on img
elementsUse a regular a
element to link to the
description, or (in the case of images) use an image
map to provide a link from the image to the image's
description.
lowsrc
on img
elementsUse a progressive JPEG image (given in the src
attribute),
instead of using two separate images.
target
on link
elementsUnnecessary. Omit it altogether.
scheme
on meta
elementsUse only one scheme per field, or make the scheme declaration part of the value.
archive
on object
elementsclassid
on object
elementscode
on object
elementscodebase
on object
elementscodetype
on object
elementsUse the data
and type
attributes to invoke plugins. To set parameters with these names
in particular, the param
element can be used.
declare
on object
elementsRepeat the object
element completely each time the resource is to be reused.
standby
on object
elementsOptimize the linked resource so that it loads quickly or, at least, incrementally.
type
on param
elementsvaluetype
on param
elementsUse the name
and value
attributes without declaring
value types.
language
on script
elements (except as noted in the previous section)Use the type
attribute
instead.
event
on script
elementsfor
on script
elementsUse DOM Events mechanisms to register event listeners. [DOMEVENTS]
datapagesize
on table
elementsUnnecessary. Omit it altogether.
abbr
on td
and th
elementsUse text that begins in an unambiguous and terse manner, and include any more elaborate text after that. The title
attribute can also be useful in including more detailed text, so that the cell's contents can be made terse.
axis
on td
and th
elementsdatasrc
on a
, applet
, button
, div
, frame
, iframe
, img
, input
, label
, legend
, marquee
, object
, option
, select
, span
, table
, and textarea
elementsdatafld
on a
, applet
, button
, div
, fieldset
, frame
, iframe
, img
, input
, label
, legend
, marquee
, object
, param
, select
, span
, and textarea
elementsdataformatas
on button
, div
, input
, label
, legend
, marquee
, object
, option
, select
, span
, and table
elementsUse script and a mechanism such as XMLHttpRequest
to populate the page dynamically. [XHR]
alink
on body
elementsbgcolor
on body
elementslink
on body
elementsmarginbottom
on body
elementsmarginheight
on body
elementsmarginleft
on body
elementsmarginright
on body
elementsmargintop
on body
elementsmarginwidth
on body
elementstext
on body
elementsvlink
on body
elementsclear
on br
elementsalign
on caption
elementsalign
on col
elementschar
on col
elementscharoff
on col
elementsvalign
on col
elementswidth
on col
elementsalign
on div
elementscompact
on dl
elementsalign
on embed
elementshspace
on embed
elementsvspace
on embed
elementsalign
on hr
elementscolor
on hr
elementsnoshade
on hr
elementssize
on hr
elementswidth
on hr
elementsalign
on h1
—h6
elementsalign
on iframe
elementsallowtransparency
on iframe
elementsframeborder
on iframe
elementshspace
on iframe
elementsmarginheight
on iframe
elementsmarginwidth
on iframe
elementsscrolling
on iframe
elementsvspace
on iframe
elementsalign
on input
elementshspace
on input
elementsvspace
on input
elementsalign
on img
elementsborder
on img
elements (except as noted in the previous section)hspace
on img
elementsvspace
on img
elementsalign
on legend
elementstype
on li
elementscompact
on menu
elementsalign
on object
elementsborder
on object
elementshspace
on object
elementsvspace
on object
elementscompact
on ol
elementsalign
on p
elementswidth
on pre
elementsalign
on table
elementsbgcolor
on table
elementsborder
on table
elementscellpadding
on table
elementscellspacing
on table
elementsframe
on table
elementsrules
on table
elementswidth
on table
elementsalign
on tbody
, thead
, and tfoot
elementschar
on tbody
, thead
, and tfoot
elementscharoff
on tbody
, thead
, and tfoot
elementsvalign
on tbody
, thead
, and tfoot
elementsalign
on td
and th
elementsbgcolor
on td
and th
elementschar
on td
and th
elementscharoff
on td
and th
elementsheight
on td
and th
elementsnowrap
on td
and th
elementsvalign
on td
and th
elementswidth
on td
and th
elementsalign
on tr
elementsbgcolor
on tr
elementschar
on tr
elementscharoff
on tr
elementsvalign
on tr
elementscompact
on ul
elementstype
on ul
elementsbackground
on body
, table
, thead
, tbody
, tfoot
, tr
, td
, and th
elementsUse CSS instead.