$0
+ is not allowed for HTML document.The character encoding used for the document is not allowed + for HTML document. The document is non‐conforming.
+$0
+ 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.
+Use of UTF-8 as the character encoding of the document is encouraged, + though the use of another character encoding is 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+ is obsolete.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.
$0
+ 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-nameExistence 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.
$0, a character encoding declaration specifying
+ character encoding as $1 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 the 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.<$0>
+ is not allowed after the end tag </body>.The start or 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.
& character must
introduce a reference.An & (U+0026
- AMPERSAND) character which
+
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;</ 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
@@ -93,7 +261,7 @@
The string &# must be the first two characters
of a reference:
-
&#d;<! 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
@@ -166,19 +390,47 @@
/>) cannot be
+ />) cannot be
used for this element.Void element syntax (/>) must not be used
+
Polytheistic slash (/>) must not be used
for the element. The document is non-conforming.
The void element syntax can only be +
The polytheistic slash can only be
used for base, link, meta,
hr, br, img,
embed, param, area,
col, and input elements.
Note that, unlike in XML, the void element syntax has +
<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.
<?...?>) cannot be used.<?...>) cannot be used.Processing instructions (<?...?>),
including XML declaration (<?xml ...?>)
and XML style sheet PI
- (<xml-stylesheet ...?>), are not allowed
+ (<?xml-stylesheet ...?>), are not allowed
in the HTML syntax. The document is non-conforming.
If it is necessary to embed a processing instruction - in the HTML document, you must use the XML syntax instead.
- -In the HTML syntax, XML declaration is not necessary.
- -Instead of XML style sheet,
- PIs, you must
- use the HTML link element whose rel
- attribute is set to stylesheet (or
- alternate stylesheet for an aleternate style sheet).
<?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 browsers, will display processing instructions + some mobile Web browsers, will display processing instructions as string.
<$0>
- is not allowed in a body element.body element.
The start or end tag of an element, which
cannot be a descendant of There is a start tag Only white space characters and comments are allowed
- before the body element, appears
@@ -269,7 +543,7 @@
<head>
+ <head>
is not allowed in the head element.<head> in the
@@ -344,7 +618,8 @@
DOCTYPE.DOCTYPE. XML declaration is not
+ allowed in HTML document.
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.
The document contains a DOCTYPE declaration
that is different from HTML5 DOCTYPE (i.e.
- <!DOCTYPE HTML>). The document is non-conforming.
<!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 @@ -404,6 +702,19 @@
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 element$0 child element.
The document is non-conforming.
- For example: -
head element must contain exactly one
- title child element.tr
- element must contain one or more td or th
- child element.head elementtitle child element.html elementhead child element followed
+ by a body element.tr elementtd or th child element.An element appears where it is not allowed. The document is non-conforming.
-Note: The conformance checker does - not support form elements yet.
-Possible causes:
Any inline-level content must be put
in e.g. paragraph element such as p.
div, hn, or
- sectionThough 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.
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.html element
- that is the root element of an XHTML documentIn an XHTML document, the root html
- element must have an xmlns attribute
- whose value is set to
- http://www.w3.org/1999/xhtml.
blink,
+ center, or marquee elementbutton, datalist,
+ fieldset, form,
+ input, label,
+ optgroup, option, output,
+ rb, rp, rt, ruby,
+ textarea, or textarea elementAn 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.
$0
@@ -545,11 +908,35 @@
is non-conforming.
Some attribute is defined as required.
- For example, any img element must have
- alt and src attributes specified.
Without required attributes specified, user agents
- cannot provide the 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.{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.xml:lang attribute is not
allowed in HTML document.The xml:lang attribute is not allowed in
HTML document. The document is non-conforming.
The lang attribute in the null
- namespace for HTML elements is defined as conforming only for
- XML document.
Use of the xml:lang attribute is conforming
+ only in XML documents.
To specify natural language information in HTML document,
use lang attribute instead.
The lang attribute in null
- namespace for HTML elements is defined as conforming only for
- HTML document.
To specify natural language information in XML document,
use xml:lang attribute instead.
The xmlns attribute in the null
namespace is not allowed in XHTML document.
This error should not occur in conformance-checking +
This error should not occur in conformance-checking of static documents.
$0
+ is not registered.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.
+$0 is a private
+ character encoding 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.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.
+{@} 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">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">contentsindex.copyrightlicense.homeindex.previousprev.startfirst.toctoc or topindex.$1
+ is different from document character encoding
+ $0.The specified character encoding name is different from + the character encoding of the document. The document + is non‐conforming.
+Warning: The data served to the conforming checker might be out of date; it might have already - been accepted or rejected, depending on which the document - might be conforming or non-conforming. See WHATWG Wiki + been accepted or rejected. The document might or might not be + conforming depending on the status. See WHATWG Wiki for the latest information.
For example, the table below is non-conforming: -
<table>
+ <table>
<tbody>
<tr><td rowspan=2></td></tr>
</tbody>
</table>
- ... is non-conforming, since the second row contains only
- a cell that spans the first and the second rows.
+ ... since the second row contains only
+ a cell that spans between first and second rows.
@@ -777,6 +1298,23 @@
class="should" level="s">
{@}: An obsolete
subtype is used.
+ The specified Internet Media Type is registered with status
+ of OBSOLETE.
+
+
+ - Media type
text/ecmascript
+ - Media type
text/ecmascript is obsoleted in
+ favor of application/ecmascript. Note that
+ text/javascript would be better alternative
+ for many cases.
+ - Media type
text/javascript
+ - Media type
text/javascript is obsoleted by
+ IETF with backward incompatible alternate
+ application/javascript for architectural
+ purity. Realist may ignore this warning.
+
+
-
-URI (or IRI) Warnings
+
+URI (or IRI) Should-level Errors
- Dot-segment (. or
- ..) should not occur in an absolute reference.
+ A dot-segment (. or
+ ..) occurs in an absolute reference.
Dot-segment (. or ..) should
not occur in an absolute reference.
@@ -839,14 +1377,22 @@
- This IRI should explicitly end with
- /.
+ This IRI does not end with
+ a /.
+
+ The IRI does not end with a /. If there is an
+ authority component in an IRI, a / should be present
+ instead of empty path component.
+
+ For example, http://www.example.com/
+ is preferred to http://www.example.com.
+
- Hexadecimal digit in percent-encoding
- should be in lowercase.
+ A lowercase hexadecimal digit is used
+ in percent-encoding.
The hexadecimal digit in percent-encoding string in the IRI
is in lowercase. Though the IRI is conforming,
@@ -887,34 +1433,119 @@
+
+Cache Manifest Errors
+
+
+ This document is not a cache manifest.
+
+ 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).
+
+
+
+
+
+Stability Information
+
+
+ This element is in the
+ call‐for‐implementation phase.
+
+ The element is in the call‐for‐implementation phase.
+
+ 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 HTML4, Atom 1.0, and XBL 2.0 belong to this
+ class.
+
+
+
+
+ This element is in the last
+ call‐for‐comments phase.
+
+ The element is in the last call‐for‐comments phase.
+
+ 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.
+
+
+
+
+ This element is documented in a working
+ draft.
+
+ 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.
+
+
+
+
+ This element is not part of any
+ standard.
+
+ The element is not part of any standard or draft.
+
+ The element should not be used for any practical purpose.
+
+
+
+
Unsupported Messages
-
- This attribute is not supported by the
- conformance checker; it might or might not be conforming.
+ Conformance checking for element
+ {local-name} is not supported; it might or
+ might not be conforming.
- The conformant checker does not support the attribute.
+
The conformant checker does not support the element.
It cannot determine whether the document is conforming or not.
-
- This element is not supported by the
- conformance checker; it might or might not be conforming.
+ Conformance checking for attribute
+ {local-name} of element
+ {element-local-name} is not supported;
+ it might or might not be conforming.
- The conformant checker does not support the element.
+
The conformant checker does not support the attribute.
It cannot determine whether the document is conforming or not.
- The link type $0 is not
+ Link type $0 is not
standardized or registered at the time of the release of the conformance
- checker; it is non-conforming unless it has now been
+ checker; it is non-conforming unless it now has been
registered.
The rel attribute is defined as a list of link types.
@@ -927,6 +1558,12 @@
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.
+
+
+ - Link types
shortcut icon
+ - Link type
shortcut is not registered.
+ Use only icon for linking to so-called favicon.
+
@@ -936,12 +1573,6 @@
is not supported; it might or might not be conforming.
-
- Conformance checking for language tag
- is not supported; it might or might not be conforming.
-
-
Conformance checking for media query
@@ -973,14 +1604,68 @@
manakaiIsHTML:0;;XML Document
+
+Error Levels
+
+
+
+Level
+Conforming?
+Description
+
+MUST‐level error
+Non‐conforming.
+A violation to a hard requirement of the specification.
+The document is non‐conforming.
+
+
+SHOULD‐level error
+Non‐conforming, but in some case
+conforming.
+A violation to a requirement of the specification.
+The violation might be legitimize in some case. Otherwise,
+the document is non‐conforming.
+
+
+Warning
+Conforming.
+A warning is an advice from the conformance checker to avoid
+to solve a problem in a confusing or possibly wrong way.
+It does not affect to the conformance of the document, and
+may sometimes be inappropriate.
+
+
+Information
+Conforming.
+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.
+
+
+Not supported
+Unknown.
+Some feature that is not supported by the conformance checker
+is used in the document.
+
+
+
+
+
License of This Document
-Copyright 2007 Wakaba
-This library is free software; you can redistribute it
+
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.
-
+