<$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
@@ -38,6 +53,9 @@
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:
</ 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.
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:
-
<lt;<The string &# must be the first two characters
- NUMBER SIGN) character must be the first two characters
of a reference:
To represent &# as data characters, use
- named entity reference:
+ a named entity reference for the & character:
&#To represent &#x as data characters, use
- named entity reference:
+ 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 documents.<!<! 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
@@ -154,7 +248,8 @@
$0.There are more than one attributes with the same name in a tag. The document is non-conforming.
@@ -166,23 +261,91 @@/>) 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/>Note that, unlike in XML, the polytheistic slash has no effect in HTML.
<?...>) cannot be used.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.<?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).<?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.
+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.
<$0>
- is not allowed in body.body element.The start or end tag of an element, which
cannot be a descendant of body element, appears
@@ -225,10 +400,24 @@
<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.
<$0>
- is not allowed in table.table element.
The start or end tag of an element, which
cannot be a child of The document does not start with a Only white space characters and comments are allowed
- before the table element, appears
@@ -277,7 +466,7 @@
DOCTYPE.DOCTYPE.
@@ -288,7 +477,8 @@
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.
<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.
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 @@ -330,6 +560,19 @@
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 elementPossible causes: -
a or span)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.
div or hn)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.
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.
$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: -
a or span)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.
div or hn)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.
html elementIn an XHTML document, the root html
- element must have an xmlns attribute
- whose value is set to
- http://www.w3.org/1999/xhtml.
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 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 an XHTML document, the root html
+ element must have an xmlns attribute
+ whose value is set to
+ 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/2004/Atom
+ namespace.
The conformance checker does not support Atom 0.3. + Use Atom 1.0 for feed documents.
$0
+ 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.
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.
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).
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.
{@} 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 Default-Style and Refresh
+ is 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 charset declaration syntax
+ <meta http-equiv="Content-Type" content="text/html; charset=charset-name">
+ is in use. The document is non‐conforming.
The new charset declaration syntax is: +
<meta charset="charset-name">$0
cannot be specified for this element.$0
is non-conforming.The specified link type is non-conforming. The entire document - is non-conforming.
+The specified link type is non-conforming, and therefore + the document is non-conforming.
-For example, in place of non-conforming link type copyright
- you must use link type license.
contentsindex.copyrightlicense.homeindex.previousprev.startfirst.toc or topindex.{@} is reserved.The specified browsing context name is reserved. The document is non-conforming.
@@ -592,7 +987,7 @@ browsing context names_blank,
_main, and _replace.
However, they are not conforming attribute values.
- 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.
@@ -636,6 +1031,28 @@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>{@}: An obsolete
+ subtype is used.The specified Internet Media Type is registered with status + of OBSOLETE.
+ +text/ecmascripttext/ecmascript is obsoleted in
+ favor of application/ecmascript. Note that
+ text/javascript would be better alternative
+ for many cases.text/javascripttext/javascript is obsoleted by
+ IETF with backward incompatible alternate
+ application/javascript for architectural
+ purity. Realist may ignore this warning.x- or x.)
- subtype is used.{@}: A private
+ (x- or x.) subtype is used.{@}: The subtype is
+ not registered to IANA.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.. or
- ..) should not occur in an absolute reference.. or
+ ..) occurs in an absolute reference.Dot-segment (. or ..) should
not occur in an absolute reference.
/./.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.
The hexadecimal digit in percent-encoding string in the IRI is in lowercase. Though the IRI is conforming, @@ -717,36 +1175,78 @@
The scheme part of the IRI is written in uppercase letter.
+ +Uppercase scheme names are not required to be processed + correctly.
+ +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).
{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.
{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.
$0 is not
+ $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.
@@ -759,6 +1259,12 @@
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.
shortcut iconshortcut is not registered.
+ Use only icon for linking to so-called favicon.| 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. | +
| Not supported | +Unknown. | +Some feature that is not supported by the conformance checker +is used in the 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.