WebHACC is a conformance checker (or validator) for Web documents, supporting latest Web standards including HTML5, Atom 1.0, CSS3.
{octets}
is not an allowed representation of the character
{char} — character reference
{char:hexref} should be used instead.{octets}.{octets}
is illegal.The input stream is encoded in ISO-2022-JP
or its variant but is partially broken.
Note that an ISO-2022-JP stream must end in the ASCII
state.
{octets}.{value}
is not supported and the explicit character encoding specification is
ignored. The result of the conformance checking might be
wrong.{text}
is not allowed for HTML document.The character encoding used for the document is not allowed for HTML document. The document is non‐conforming.
{text}
should not be used for HTML document.The character encoding used for the document is not recommended for HTML document. The document is non‐conforming unless there is any good reason to use that encoding.
{text}).Use of UTF-8 as the character encoding of the document is encouraged, though the use of another character encoding is still conforming.
The conformance checker cannot detect whether the input document met the requirements on character encoding, since the document is not inputed as a serialized byte sequence. The document is not conforming if it is not encoded in an appropriate character encoding with appropriate labeling.
The document does not contain a character encoding declaration. Unless the character encoding is explicitly specified in lower‐level protocol, e.g. in HTTP, or is implied by BOM, there must be a character encoding declaration. The document is non‐conforming.
The long character encoding declaration syntax
<meta http-equiv="Content-Type" content="text/html; charset=charset-name">
is obsolete. The new syntax is:
<meta charset="charset-name">
Note that the encoding declaration in XML
declaration has no effect for HTML document.
{text}
is not a superset of ASCII.The document is not labeled with character encoding name in lower‐level protocol, e.g. in HTTP, and the document is not begin with BOM. In addition, the character encoding of the document is not a superset of ASCII. The document is non‐conforming.
Unless there is a BOM, the character encoding for the document must be specified in e.g. HTTP‐level, as:
Content-Type: text/html; charset=charset-name
Existence of HTML character encoding declaration, i.e.
<meta charset="charset-name">,
does not allow to omit charset parameter
for HTML document encoded in non‐ASCII
compatible encoding.
Character encodings Shift_JIS, Windows-31J,
and ISO-2022-JP are not a superset of
ASCII for the purpose of HTML conformance.
{text} (Sniffed because no explicit specification
for the character encoding of this document is found in the transfer
procotol headers).{text} because no explicit specification
for the character encoding of this document is found in the transfer
procotol headers.The conformance checker cannot find an appropriate decoder for the character encoding used to encode characters in the document.
This error is raised if:
In either case, the result shown by the conformance checker might contain wrong errors caused by errorneous decoder or might not contain errors that should be raised if an appropriate decoder is used.
{text} is not supported.{text} is same as the character encoding specified
in the character encoding declaration. This is not an
error.{text}, a character encoding declaration specifying
a different character encoding is found. The document
is reparsed.While parsing a document in a character encoding, a character encoding declaration which declares the character encoding of the document as another character encoding is found. The occurence of this warning itself does not make the document non‐conforming. However, the failure of the first attempt to to detect the character encoding might be a result of non‐conformance of the document.
The document will be reparsed from the beginning. Some error or warning might be reported again.
These are suggestions to avoid this warning:
charset parameter in the Content-Type
field in the HTTP header, as:
Content-Type: text/html; charset="charset-name"<meta charset="charset-name">)
just after <head> start tag.UTF-8.NULL character
is not allowed.{text} is
not allowed.{text}
is found in the input stream.Noncharacter code points are used in the input stream.
Noncharacter code points are reserved for internal processings. Their use for information interchanges are forbidden.
In addition, they are not allowed in HTML document.
{text} is not
a Unicode character.{text}
is deprecated.{text}
is discouraged.{text}
is not the preferred representation of that character.{text}
should not be used in many cases.", ', and =."
or ' if it contains a ", ', or
= character.In an unquoted attribute value, a character "
(U+0022 QUOTATION MARK),
' (U+0026
APOSTROPHE), or =
(U+003D EQUAL SIGN)
is contained. These characters are not allowed in unquoted attribute
values, since they are used to quote attribute values or to separate
attribute name and value.
This error is also raised if one try to use empty attribute
value like <foo bar= baz=>;
in this example, baz= is
treated as an invalid attribute value for the attribute
bar, not as another attribute.
& character must
be escaped as &.An & character which
is not part of any reference appears in the input stream.
The document is non‐conforming.
Any & character in URI (or IRI)
must be escaped as &.
The & character must
be the first character of a reference:
&entity-name;
where entity-name is the name of the
character entity to be referenced.
&#d;
where d is the decimal representation of
the code position of the character to be referenced.
&#xh;
where h is the hexadecimal representation
of the code position of the character to be referenced.To represent & as a data character, use
named entity reference:
&
</ string is not followed
by a tag name.There is a < (U+003C
LESS-THAN SIGN) character
immediately followed by a / (U+005F
SOLIDUS) character, which is not part
of any end tag, in the input stream. The document
is non-conforming.
The </ sequence immediately followed
by an EOF is
interpreted as a string data of </.
The </ sequence as string data must
be escaped as:
</
< character is not followed
by tag name or by a ! character.A < (U+003C
LESS-THAN SIGN) character which is not part
of any markup appears in the input stream.
The < character as a data character must
be escaped as:
<
&#.An & (U+0026
AMPERSAND) character immediately
followed by a # (U+0023
NUMBER SIGN) character which
is not part of any reference appears in the input stream.
The document is non-conforming.
The string &# must be the first two characters
of a reference:
&#d;
where d is the decimal representation of
the code point of the character to be referenced.
&#xh;
where h is the hexadecimal representation
of the code point of the character to be referenced.To represent &# as data characters, use
a named entity reference for the & character:
&#
&#x.The string &#x or &#X which
is not part of any reference appears in the input stream.
The document is non-conforming.
The string &#x or &#X must
be the first three characters of a hexadecimal reference:
&#xh;
where h is the hexadecimal representation
of the code point of the character to be referenced.
To represent &#x as data characters, use
a named entity reference for the & character:
&#x
<! is not followed
by --.There is a < (U+003C
LESS-THAN SIGN) character
followed by a ! (U+0021
EXCLAMATION MARK) character,
which is not followed by a -- or
!DOCTYPE. The document is non-conforming.
<!-- (<!
immediately followed
by two -s) and must be terminated by
-->.
Strings <! not followed
by -- and <!- not followed by
- are not valid open delimiters for comments.CDATA sectionsDOCTYPE
and comment declarations, are not allowed in HTML document.<!<! must be escaped as
<!.</ is not followed
by tag name.There is a < (U+003C
LESS-THAN SIGN) character
immediately followed by a / (U+005F
SOLIDUS) character, which is not part
of any end tag, in the input stream. The document
is non-conforming.
The </ sequence not followed by a
tag name is parsed as an opening of bogus comment.
The </ sequence as string data must
be escaped as:
</
-- sequence
in a comment.There is a - (U+002D
HYPHEN-MINUS) character
at the end of the comment or a -- sequence
in the comment. The document is non-conforming.
Comments cannot contain a string --, as in XML.
Unlike SGML, there cannot be more than one comments
(where comment is an SGML term) in the comment
declaration.
{text}.There are more than one attributes with the same name in a tag. The document is non-conforming.
The motion attribute is not part of the HTML standard.
Use img element with animation GIF instead.
<>) is not
allowed.</>) is not
allowed.The attribute value is not specified after the =
(U+003C EQUAL SIGN)
character.
When an attribute value is empty, the = character after
the attribute name must be specified as:
<foo bar>
Instead, quotation marks can be used to explicitly represent that the attribute value is empty, as:
<foo bar="">
... or like:
<foo bar=''>
{text} is not allowed./>) cannot be
used for this element.Polytheistic slash (/>) must not be used
for the element. The document is non-conforming.
The polytheistic slash can only be
used for base, link, meta,
hr, br, img,
embed, param, area,
col, and input elements.
<script/>The polytheistic slash cannot be used for script
element. Even for an empty script element,
there must be an explicit end tag
</script>.
NOTE: Though some user agents interpret
polytheistic slash for script element as the
closing of the element, such usage is not allowed under
the current standard.
<basefont/>, <bgsound/>,
<frame/>, <keygen/>,
<spacer/>, <wbr/><command/>, <event-source/>,
<nest/>, or <source/><a/>, <p/>
<p></p>
Note that, unlike in XML, the polytheistic slash has no effect in HTML.
<!DOCTYPE , the
document type name must be specified.PUBLIC, no
oublic identifier is specified.; character.<!DOCTYPE, there
must be at least a white space character before the document type
name.SYSTEM, no
system identifier is specified.<?...>) is not allowed in HTML
document.Processing instructions (<?...?>),
including XML declaration (<?xml ...?>)
and XML style sheet PI
(<?xml-stylesheet ...?>), are not allowed
in the HTML syntax. The document is non-conforming.
<?xbl?> (XBL Association)binding property in CSS
style sheet as:
<style>
p {
binding: url(binding.xbl);
}
</style>
<?xml?> (XML declaration)<?xml-stylesheet?> (XML style sheet
PI)link element with rel
attribute set to stylesheet (or,
alternate stylesheet for an alternate style
sheet).
<link rel=stylesheet href="path/to/stylesheet.css">
<?php?> or
<? ... PHP code ... ?>
(PHP code)ProcessingInstruction node by scripting.Web browsers will parse processing instructions as bogus comments. Some legacy Web browsers, such as IE:mac and some mobile Web browsers, will display processing instructions as string.
PUBLIC.SYSTEM.-->.DOCTYPE is not closed by a
> character.>
character.<{text}> is after the html element
is closed.</{text}> is after the html element
is closed.<{text}> is
not allowed after the body is closed.</{text}> is
not allowed after the body is closed.body is closed.<{text}> is
not allowed after the frameset is closed.</{text}> is
not allowed after the frameset is closed.frame is closed.{text} element cannot be
inserted between head and body
elements.A start tag appears after the head element is closed
but before the body element is opened.
The document is non-conforming.
<{text}> is
not allowed after the html is closed.The start tag of an element appears after the
body element has been closed. The document is
non-conforming.
Any content of the document other than head
contents and comments must be put into the body
element.
</{text}> is
not allowed after the html is closed.The end tag of an element appears after the
body element has been closed. The document is
non-conforming.
Any content of the document other than head
contents and comments must be put into the body
element.
html is closed.image element is
obsolete.HTML a elements cannot be nested.
The document is non-conforming.
In the HTML syntax, a start tag of the a
implies the end tag of any opening a element.
<{text}>
is not allowed in the body element.The start or end tag of an element, which
cannot be a descendant of body element, appears
in the input stream while the body element has been opened.
The document is non-conforming.
button element cannot be
nested.<form> is
not allowed in a form element.<{text}> is
not allowed in a framset element.</{text}> is
not allowed in a frameset element.frameset element.<head>
is not allowed in the head element.There is a start tag <head> in the
<head> element. The document is non-conforming.
In an HTML document there must not be more than
one head element, therefore no more than one
start tag <head> can appear in the input stream.
DOCTYPE appears after any
element or data character has been seen.A DOCTYPE appears after any element or data character
has been seen. The document is non-conforming.
The DOCTYPE must be placed before any
tag, reference, or data character. Only white space characters
and comments can be inserted before the DOCTYPE.
nobr element cannot be
nested.{text} element is not
allowed in a noscript element in the
head element.</{text}>
appers before the noscript element is closed.noscript element is not closed
before the end of file.noscript element in the head
element.<{text}>
is not allowed in a select element.</{text}>
is not allowed in a select element.<{text}>
is not allowed in a table element.The start or end tag of an element, which
cannot be a child of table element, appears
in the input stream while the table element has been opened
but no other element has been opened. The document is non-conforming.
In table, only table related elements
are allowed; any other element must be contained in
td or th element to form
a part of the table, or caption element to create
a table caption.
</{text}>
is not allowed in a table element.table element, outside of the caption and cells.A non‐white‐space character appears in table.
The document is non-conforming.
In table, only table related elements
are allowed; any other element and data character must be contained in
td or th element to form
a part of the table, or caption element to create
a table caption.
isindex element is
obsolete.tr
element is missing.Start tag of a tr element, which is not
optional, is missing. The document is non-conforming.
In a table section, a <tr> start tag
must occur before any <td> or
<th> start tag. Though the HTML5 parser
implies the <tr> start tag before
these start tags, it must be explicitly specified.
DOCTYPE.The document does not start with a DOCTYPE.
The document is non-conforming.
An HTML document must start by a DOCTYPE:
<!DOCTYPE HTML>
Only white space characters and comments are allowed
before the DOCTYPE. XML declaration is not
allowed in HTML document.
{text} is not
closed.End tag of an element is not found before, for example, an end tag of another element appears or the end of the document. The document is non-conforming.
Only body, colgroup, dd,
dt, head, html, li,
ol, option, optgroup,
p, rb, rp, rt,
tbody, td, tfoot,
th, thead, tr,
ul end tag can be omitted in HTML documents.
For any element except for void element, there must be an explicit
end tag.
canvas elementcanvas element is no longer
defined as empty. There must be an end tag
</canvas>.Note that misnesting tags, such as
<a><b></a></b>, are not
allowed and they also cause this error.
<html> tag is not
the first start tag.There is a start tag of the html element
that it not the first start tag in the input stream.
The document is non-conforming.
In an HTML document, there cannot be more than one
html element and therefore there cannot be
more than one <html> tag. In addition,
nothing can be placed before the <html> tag
except a DOCTYPE, white space characters,
and comments.
The document contains a DOCTYPE declaration
that is different from HTML5 DOCTYPE (i.e.
<!DOCTYPE HTML>).
The document is non‐conforming.
The document might or might not be conformant to some version of HTML. However, conformance to any HTML specification other than HTML5 provides for no practical convenience, since Web borwsers will parse any HTML document (roughly) as defined in HTML5.
<{text}> is
not allowed here.{text} is not
opened.An end tag appears though no element with the same name has been opened. The document is non-conforming.
For any end tag in HTML document, there must be a corresponding start tag.
base, basefont,
bgsound, br, col,
embed, frame, hr,
image, img, input,
isindex, link, meta,
param, spacer, or wbr elementDOCTYPE legacy string is
used.The DOCTYPE with the DOCTYPE legacy
string, i.e.
<!DOCTYPE HTML PUBLIC "XSLT-compat">
is used.
The DOCTYPE legacy string should not be used for documents
not generated from XSLT transformation process. It is allowed
only to enable to use XSLT style sheets with the HTML output mode, which
does not support generation of the DOCTYPE with no
PUBLIC
identifier. For other purposes, the DOCTYPE legacy
string, i.e. PUBLIC "XSLT-compat",
is useless and should not be used.
base element with the
href attribute specified cannot be placed after
any attribute with a URL.base element with the
target attribute specified cannot be placed after
any element that defines a hyperlink.A data character appears where it is not allowed in this context. The document is non-conforming.
Possible causes:
A data character cannot be a child
of certain sectioning elements such as body,
section, and blockquote.
Any inline-level content must be put
in e.g. paragraph element such as p.
Though some elements such as div,
li, and td allow
either one of block-level or inline-level content
is allowed. If there is a block-level content,
any inline-level content must be put
in e.g. paragraph element such as p.
{text} as a child of this element.The content model of the element is so defined that it
must contain a $0 child element.
The document is non-conforming.
head elementtitle child element.html elementhead child element followed
by a body element.tr elementtd or th child element.td
or th element as a child of this element.The tr element must contain at least one
td or th child element. The document
is non-conforming.
{text} in the Atom namespace as a child of this
element.link element
whose rel attribute is set to alternate as a
child of this element.link element
whose rel attribute is set to self as a
child of this element.hn element descendant.An element appears where it is not allowed. The document is non-conforming.
Possible causes:
a, progress, or imgAn inline-level element cannot be a child
of certain sectioning elements such as body,
section, and blockquote.
Any inline-level content must be put
in e.g. paragraph element such as p.
aside,
div, hn,
p, or sectiondiv,
li, td, or thThe parent element allows either
block-level or inline-level content. If there is a
block-level content, any inline-level content must be
put in e.g. paragraph element such as p.
For example, an HTML document fragment
<div><p>Hello!</p> World!</div>
is non-conforming, since a word World!
does not belong
to any paragraph. (If not part of any paragraph, what is
it!?) A conforming example would be:
<div><p>Hello!</p> <p>World!</p></div>
div element cannot be
a child of an h1 element.noscript elementnoscript element is allowed only in the context
where a block-level or inline-level content is expected
and in the head element.
It cannot be used in e.g. ul, table,
or select.blink,
center, or marquee elementbutton, datalist,
fieldset, form,
input, label,
optgroup, option, output,
rb, rp, rt, ruby,
textarea, or textarea elementarea element cannot be used
outside of a map element.base
element.datatemplate element, only
rule elements are allowed.details or fieldset
element, only at the beginning of the element a legend element
may be used.figure element, only at the
beginning or only at the end of the element a lengend element
may be used.style element without
scoped attribute is not allowed in this context.noscript element in the head element.style element with
scoped attribute is not allowed in the head
element.title
element.head element.The character encoding declaration
(<meta charset="..."> or
<meta http-equiv=Content-Type content="text/html; charset=...">
must be the first child element in the head element.
The character encoding declaration have to occur near the beginning of the document to ensure that Web browsers can be determine the character encoding of the document.
The title element and other metadata elements must
appear after any character encoding declaration is processed.
An element that is not allowed as the root element is used as the root element of the document. The document is non-conforming, as far as the conformance checker can tell.
html element in an XHTML documentIn XHTML document, the root html
element must have an xmlns attribute as:
<html xmlns="http://www.w3.org/1999/xhtml">rss elementThe document is written in some version of RSS.
The conformance checker does not support any version of RSS. Use Atom 1.0 for feed documents.
feed elementThe Atom feed element must be
in the http://www.w3.org/2005/Atom
namespace as:
<feed xmlns="http://www.w3.org/2005/Atom">
The conformance checker does not support Atom 0.3. Use Atom 1.0 for feed documents.
ruby
element.content element.The element is not one of elements allowed in the latest version of relevant specifications.
The element cannot be used.
event-source elementeventsource
element (no hyphen).m elementmark
element.label element.{text}
element before this element.There must be an element before another element, but there is not. The document is non-conforming.
For example, there must be a dt element
before any dd element.
rp element must
be a parenthesis.{text}
is not specified.A required attribute is not specified. The document is non-conforming.
Some attribute is defined as required. Without required attributes specified, user agents cannot provide full functionality of the element to the user.
img elementsrc attribute must be specified.
Additionally, the alt attribute must be specified
in many cases.link elementrel attribute must be specified.
Note that the rev attribute is obsolete.object at least one of
data and type attributes must be
specified.base element, at least one of
href and target attributes must be
specified.meta element with the
content attribute specified, exactly one of
name and http-equiv attributes must be
specified.meta element, exactly one of
name, http-equiv, and charset
attributes must be specified.{local-name} is not allowed for
{element-local-name} element.An attribute is specified where it is not allowed. The document is non-conforming.
meta elementmeta element, only one of
name, http-equiv, or charset
attribute is allowed.ismap attribute may only be
used for the image contained in an a element.The attribute is not one of attributes allowed for the element in the latest version of relevant specifications.
The attribute cannot be used.
align attribute (various HTML elements)border attribute (various HTML elements)autosubmit attribute (menu element)language attribute (script element)<script>
/* JavaScript code */
</script>
type attribute, as follows:
<script type="text/javascript">.<script type="text/vbscript">.value attribute cannot be
specified to an input element whose type
is hidden and name is
_charset_.xml:lang attribute in HTML
document is ignored.The xml:lang attribute does not have an effect in
HTML document.
The xml:lang attribute is only applicable to XML
documents. In HTML document, it is only allowed to ease migration
from XML.
To specify natural language information in HTML document,
use lang attribute instead.
XHTML 1.0 Appendix C was encouraged to specify both
lang and xml:lang attributes with
the same value. Such a duplication has no effect in practice.
Use only one of lang (in HTML) or xml:lang (in
XML).
charset attribute is not
allowed in XML document.The charset attribute of a
meta element is not allowed in XML document.
The document is non-conforming.
To specify the character encoding used for serialization, if necessary, use XML declaration instead:
<?xml version="1.0" encoding="encoding-name"?>
noscript element cannot be
used in XML document.xml:lang attribute in no namespace
is only allowed in HTML document.xmlns attribute
in the null namespace is not allowed in
XHTML document. The document is non-conforming.The xmlns attribute in the null
namespace is not allowed in XHTML document.
This error should not occur in conformance-checking of static documents.
input element whose type is
{text}.value attribute cannot be
specified to a li element whose parent element is
not an ol element.xml:lang attribute is only allowed
when the lang attribute is specified.{@}
is not allowed. It must be an empty string or a string
{local-name}.{value}
is not ASCII compatible.{value} is not the preferred name of that
character encoding.{value} is not a registered name.The specified character encoding name is not registered to IANA. Use of registered character encoding name is a good practice to facilitate interoperability.
EUC-TWEUC-TW is not registered. Unfortunately, there
is no registered name for that character encoding. Use
Big5 encoding with character encoding name Big5
if it is enough to represent the document.ISO-2022-JP-1ISO-2022-JP-1 is not registered, nevertheless
this character encoding name is documented in
RFC 2237. Use
ISO-2022-JP-2 instead, since that character encoding
is a superset of ISO-2022-JP-1.ISO-2022-JP-3, ISO-2022-JP-3-plane1ISO-2022-JP-2004 and
ISO-2022-JP-2004-plane1.ISO-2022-JP-2003,
ISO-2022-JP-2003-plane1ISO-2022-JP-2004 and
ISO-2022-JP-2004-plane1.ISO-2022-JP-2004,
ISO-2022-JP-2004-plane1UTF-8NUTF-8N is not registered. Character encoding
name UTF-8 represents UTF-8 encoding with or
without BOM.WARNING: This error might be raised for a registered character encoding name, since the character encoding name database of the conformance checker is not complete yet.
{value} is a private name.The specified character encoding name is a private name and not registered to IANA. Use of registered character encoding name is a good practice to facilitate interoperability.
x-euc-jpEUC-JP for the Japanese EUC
character encoding.x-sjisShift_JIS for standard Shift encoding scheme of
JIS coded character set, or Windows-31J
for Microsoft standard character set as implemented by
Microsoft Windows.{value}
is syntactically not a character encoding name.The attribute value must be a character encoding name. However, the specified value is not a character encoding name syntactically. The document is non‐conforming.
Character encoding name is a string of ASCII printable characters, up to 40 characters.
coords attribute have to
contain three (3) numbers (specified:
{text}).coords attribute have to
contain four (4) numbers (specified:
{text}).coords attribute have to
contain more than or equal to six (6) numbers (specified:
{text}).coords attribute have to
contain even number of numbers (specified:
{text}).{value}
is out of range.{@} is not one
of them.For this attribute only several values are allowed and the value of the attribute is not one of them. The document is non-conforming.
meta element, http-equiv attributeOnly values Default-Style and Refresh
are allowed.
Value Content-Type is obsolete; for charset
declaration, the charset attribute can be used as:
<meta charset="charset-name">
... where charset-name is a name of the character encoding
of the document, such as utf-8.
Values Content-Style-Type and
Content-Script-Type are currently not allowed.
Value Keywords is not allowed. Use
name attribute instead of http-equiv
attribute.
Values Expires, Pragma,
and Cache-Control are not allowed;
use real HTTP header fields for cache control.
<meta http-equiv="Content-Type" content="text/html; charset=charset-name">
is obsolete.Old long character encoding declaration syntax
<meta http-equiv="Content-Type" content="text/html; charset=charset-name">
is in use. The document is non‐conforming.
The new character encoding declaration syntax is:
<meta charset="charset-name">
{@}
is not allowed.{value} is already
used for another element.{value}.{value}
appears in the attribute value twice.alt attribute value is
empty.alt attribute value is
empty.The value of the alt attribute of an area
element is an empty value.
In general, the alt attribute value cannot be empty.
It must provide an alternative text for the hyperlink represented by
the area element. The alternative text is to be used
when the Web browser cannot display the image, or is configured not
to display images.
As an exception, the alt attribute may be left blank
if the same image map (i.e. the ancestor map element)
contains another area element whose href
attribute references the same resource as the href
attribute of the area element in question, and the other
area element has an alt attribute with
non‐empty value.
title attribute
is empty.The title attribute value of the link
element that defines an alternate style sheet is an empty value.
A link element whose rel attribute
is alternate stylesheet defines an alternate style sheet.
An alternate style sheet must be associated with a name using the
title attribute. The name cannot be empty.
# character.id attribute value is
different from the name attribute value.{value}
cannot be specified for this element.The specified link type cannot be used for the element. The document is non-conforming.
Link types are associated with limited set of elements. They cannot be used with other elements.
For example, link type bookmark
can be used with a or area element,
while it cannot be used with link element.
{@}
is not an allowed value.{value}
is non-conforming.The specified link type is non-conforming, and therefore the document is non-conforming.
contentsindex.copyrightlicense.homeindex.previousprev.startfirst.toc or topindex.{value} is different from the actual document
character encoding {text}.The specified character encoding name is different from the character encoding of the document. The document is non‐conforming.
{value} matches to the actual character encoding
name cannot be checked since the input is not a byte stream.form
attribute is not a form element, or no element is
found.usemap
attribute is not a map element, or no element is
found.id
is {value} in the same table.Refresh pragma.template.{@} is reserved.The specified browsing context name is reserved. The document is non-conforming.
Names of browsing contexts starting with _
(U+005F LOW LINE)
are reserved so that it must not be used.
Old version of HTML, non-HTML markup languages, and
Web browsers define or implements special reserved
browsing context names _blank,
_main, and _replace.
However, they are not conforming attribute values.
{text}
is reserved and cannot be used for an arbitrary prefix.{text}
is reserved and cannot be used for an arbitrary namespace name.{value}
is proposed but not accepted yet; it should not be
used until it has been accepted.The link type is in the proposed status; it should not be used until it has been accepted.
Warning: The data served to the conforming checker might be out of date; it might have already been accepted or rejected. The document might or might not be conforming depending on the status. See WHATWG Wiki for the latest information.
{value}
is not a valid value.id attribute.template
attribute is not a template.value attribute value is longer
than the value of the maxlength attribute.{value} is reserved.{value} is not
allowed in this attribute.NCName.xml:lang attribute
is different from the value of the lang attribute.The value of the xml:lang attribute (either the
lang attribute in the xml (i.e.
http://www.w3.org/XML/1998/namespace) namespace, or
the xml:lang attribute in no namespace) for the element has
different value than that of the lang attribute in no
namespace.
For historical reason, there are two attributes applicable to HTML
elements to specify language information of an element: lang
and xml:lang. In HTML documents, only lang
attribute in no namespace is allowed and take effect; the
xml:lang attribute in no namespace is ignored in HTML
documents. In XHTML documents, both lang and
xml:lang attributes are allowed.
In general, only the lang attribute need to be
specified for an element.
If both lang and xml:lang attributes are
specified on the same element, their values must be the same value.
colspan attribute
results in creating a table column that does not contain
any cell anchored to it.td or
th) in the last row.rowspan attribute
results in creating a table row that does not contain
any cell anchored to it.The rowspan attribute value of the cell
is so specified that it extends a table in the row axis.
However, the extended row does not contain any cell by itself.
The document is non-conforming.
For example, the table below is non-conforming:
<table>
<tbody>
<tr><td rowspan=2></td></tr>
</tbody>
</table>
... since the second row contains only
a cell that spans between first and second rows.
rowspan attribute
results in creating a table row that does not contain
any cell anchored to it.e4x.{value}, is syntactically not a valid
attribute name.{value} is used.{value} is used.{value} is used.The specified Internet Media Type is registered with its intended usage as OBSOLETE.
text/ecmascripttext/ecmascript is obsoleted in
favor of application/ecmascript. Note that
text/javascript would be the better alternative
in many cases.text/javascripttext/javascript is obsoleted by
IETF with backward incompatible alternate
application/javascript for architectural
purity. Those who prefer reality to academic
purity may ignore this warning.{text} have to
be specified for the Internet Media Type
{value}.{value} is not
allowed for this Internet Media Type.{value} is not encouraged.{value} is not encouraged.{value} is
syntactically not a valid subtype value of an Internet Media Type.{value} is
syntactically not a valid type.{value}
is used. The conformance checker cannot determine whether use of this
parameter is valid or not.{value} is used. At the time of the update of
the conformance checker's Internet Media Type database, the subtype is
not reigstered to the IANA registry. The subtype, however, might be
registerd to the IANA registry thereafter. Please consult the IANA
registry.{value} is not encouraged since it is not
part of the IANA registry.{value} is not encouraged since it is not
a standardized type.The specified value does not satisfy the syntactical requirements for IRI references. The document is non-conforming.
Possible causes:
(U+0020
SPACE) character cannot be
used in IRI references.{text} is not defined.. or
..) occurs in an absolute reference.Dot-segment (. or ..) should
not occur in an absolute reference.
In relative references, dot-segments are used to represent
the current (.) or the parent (..)
hierarchy of the path. Though they are also allowed
in absolute references, it should be resolved to the
canonical form before it has been published.
/ character.The hexadecimal digit in percent-encoding string in the IRI is in lowercase. Though the IRI is conforming, it should be in uppercase.
An unreserved character is percent-encoded in the IRI. Though it is conforming, it should be in the decoded (or bare) form.
{value}
should be spelt in lowercase.The scheme part of the IRI is written in uppercase letter.
Uppercase scheme names are not required to be processed correctly.
{value} is
not supported by the conformance checker.) character.an+b have to be integers.an+b is
syntactically incorrect.] character.:lang
selector is not closed by a ) character.{value}
is not declared.=) is missing.*
is not followed by a | character.:-manakai-contains pseudo-class
selector.* for the universal selector) is missing.:not selector
is not closed by a ) character.:{value}
is not supported by the conformance checker.::{value}
is not supported by the conformance checker.@{text} rule is not
allowed here.@{text} rule is
syntactically incorrect.<{text}> is
already specified.hand is not valid as
<'cursor'>.<{text}>.: character is missing after
a property name.; character is missing at the
end of the property.@{value} rule is
not supported by the conformance checker.{value} is
not supported by the conformance checker.The specified document is not a cache manifest. The document is non-conforming.
An entity labeled as Internet media type
text/cache-manifest must contain a cache manifest.
A cache manifest must start with a line whose content is
CACHE MANIFEST
(exactly one space character between
CACHE and MANIFEST).
(?{text}...) is not implemented
by Perl.(?#... is
not terminated by ).(?p{...}) is
obsolete.(?p{}) is obsolete. It was deprecated in
Perl 5.8 and is no longer supported in Perl 5.10.
You can use (??{...}) instead.
(?{...})
is not terminated or {...} is not
balanced.(?(condition)...|...|...)
contains too many branches.(?({text} is used.(?... is
incomplete.(?{text})
in a regular expression has no effect.(?{text}...) is used.(... sequence
is not terminated by ).) is found.{n,m}
cannot be n > m.{text} matches
the empty string too many times.[...
is not terminated by ].\{text} sequence
is not followed by {...}.\{text}{...
is not terminated by }.\ character is not followed by
another character,\{text}
is used.\{text}
is used in a character class.[:{text}:] is used.[{text}...{text}] is used
outside of character classes.\{text}{}
is empty.{text}.{text}
is invalid., character or a ) character., character or a ) character.unsigned の後の字句が
short か long ではありません。, character or a ] character.Variadic extended attribute is seen.{text} is
specified for an attribute that is not read-only.{text}
is specified for an attribute whose type is not an interface.} character is expected.} character is expected.{text}
is not followed by a { character.Definition is
expected).Definition (optionally preceded by an extended attribute list)
is expected.{text} is
not specified.[ character.{value}
is outside of the range of the type for the constant,
{text}.{value}, is different from the type of the constant,
{text}.{text}
is already specified for another operation in the same interface.{value}
specified by extended attribute {text} is already
used for an interface.{text} is
already used.{text} is
already used.{text}
is already specified.{text} is
not defined in the fragment.{text} is
not defined in the fragment.in keyword for an argument is
found.( character for an argument
list is found.raises (or getraises
or setraises) keyword is not followed by a (
character.sequence<> type is not
terminated by a > character.sequence is not followed
by a < character.sequence<>.{text}.{text} cannot be
used in valuetype.}; sequences.{value} is
not defined in the interface specified for the attribute to which
extended attribute {text} is set.:: token is not followed by
an identifier or a DOMString keyword.{text} is not
defined.typedef of name DOMString
is ignored.{text} is used.valuetype definition does
not define DOMString as
sequence<unsigned short>.valuetype of name
DOMString is ignored.{text}, since its signature different from
the expected one.{text} is not allowed.{text}
is not applicable for an attribute whose type is not
DOMString.{text} is not specified.{text} is not allowed.{value} is
not an allowed value for extended attribute
{text}.{text}
is not applicable to this kind of object.The element is in the call for implementation stage.
Usually, using the element is safe. However, it is a new feature so that it might not be implemented correctly. If it is found that the feature is hard or impossible to implement, the feature might be revised, or in some case it might be dropped.
Elements defined by Atom 1.0 (IETF Proposed Standard), and XBL 2.0 (W3C Candidate Recommendation) belong to this class.
The element is in the last call for comments stage.
The element is relatively mature, though the standardization is not done yet. It may be used for experiments. Since it is a new feature, it might not be implemented correctly or at all. If it is found that the feature is hard or impossible to implement, the feature might be revised or might be dropped.
Elements defined by Web Forms 2.0 as well as some elements defined by HTML5 belong to this class.
The element is documented in a working or editor's draft and not yet completed.
The element should not be used for any practical purpose. The feature might be drastically changed later or might be entirely removed.
Most of new elements defined by HTML5 belong to this class.
The element is not part of any standard or draft the conformance checker is aware of.
The element should not be used for any practical purpose unless there is really a standard that defines the element.
The attribute is in the call for implementation stage.
Usually, using the attribute is safe. However, it is a new feature so that it might not be implemented correctly. If it is found that the feature is hard or impossible to implement, the feature might be revised, or in some case it might be dropped.
The attribute is in the last call for comments stage.
The attribute is relatively mature, though the standardization is not done yet. It may be used for experiments. Since it is a new feature, it might not be implemented correctly or at all. If it is found that the feature is hard or impossible to implement, the feature might be revised or might be dropped.
The attribute is documented in a working or editor's draft and not yet completed.
The attribute should not be used for any practical purpose. The feature might be drastically changed later or might be entirely removed.
The attribute is not part of any standard or draft the conformance checker is aware of.
The attribute should not be used for any practical purpose unless there is really a standard that defines the attribute.
{value}.{value}
is placed after subtag {text}.{value} is not
defined when the conformance checker is written.{value} is not in the preferred form, i.e. in
lowercase.{value} is deprecated.{text} is not allowed in the combination with this
language (and extended language) subtag(s).{text} is not registered.{value} is
not in the preferred case combination.{value} is deprecated.{value} is
not a combination of RFC 4646 subtags and is not a registered grandfathered
tag.{value} is
syntactically invalid.{value} in lowercase.{value} is deprecated.{value}
is not registered.mul should not be
used.{value}.{value}
is a private use code.{value}
is syntactically invalid.und should not be
used.{value}) is not used.{value}
is used.{value} is not
represented in the preferred case format.{value}
is syntactically invalid.{value} is
not in the preferred case combination.{value} is deprecated.{value} in uppercase.{value} is deprecated.{value}.{value}
is not registered.{value} is not allowed.{value} is
not in the preferred form, i.e. titlecase.{value} is deprecated.{value}
is not registered.{value}
is a private use code.{value}
should be suppressed when the language subtag is
{text}.{value} is
not in the preferred form, i.e. lowercase.{text} might
not be meaningful when it is used in combination with
{value}.{value} is deprecated.{value}
is specified twice.{value}
is not registered.{value}
cannot be used in this context.http://www.w3.org/1999/02/22-rdf-syntax-ns#.parseType attribute.{local-name} is not supported; it might or
might not be conforming.The conformant checker does not support the element. It cannot determine whether the document is conforming or not.
{local-name} of element
{element-local-name} is not supported;
it might or might not be conforming.The conformant checker does not support the attribute. It cannot determine whether the document is conforming or not.
{value} is not
standardized or registered at the time of the release of the conformance
checker; it is non-conforming unless it now has been
registered.The rel attribute is defined as a list of link types.
Some common link types are defined in the HTML5 specification.
Additional link types can be registered to the WHATWG Wiki.
use of any other link type is non-conforming.
The specified link type is not part of the standard or registry when the database used by the conformance cheker is created. The link type might have been added to the registry since then. In such case it might be conforming. Otherwise, the document is non-conforming.
shortcut iconshortcut is not registered.
Use only icon for linking to so-called favicon.addr-spec
is not supported; it might or might not be conforming.{text} is not supported;
it might or might not be conforming.{text} is not supported;
it might or might not be conforming.content element with type
{text} is not supported.No more information is available for this topic.
A violation to a hard requirement of the specification. The document is non‐conforming.
A violation to a requirement of the specification. The violation might be legitimize in some case. Otherwise, the document is non‐conforming.
A warning is an advice from the conformance checker to avoid solving a problem in a confusing or possibly wrong way. It does not affect to the conformance of the document, and may sometimes be inappropriate.
An informational message just provides an additional information on the feature used in the document or the status of the retrieval or so on. It does not affect to the conformance of the document.
Some feature that is not supported by the conformance checker is used in the document.
Copyright ‐
Wakaba
<w@suika.fam.cx>.
This document is free software; you can redistribute it and/or modify it under the same terms as Perl itself.