Any & character in URI (or IRI)
+ must be escaped as &.
The & character must
be the first character of a reference:
<! 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
+ <!.</ string is not followed
- by a tag name.</ is not followed
+ by tag name.There is a Void element syntax ( Polytheistic slash ( The void element syntax can only be
+ The polytheistic slash can only be
used for Note that, unlike in XML, the void element syntax has
+ The polytheistic slash cannot be used for NOTE: Though some user agents interpret
+ polytheistic slash for Note that, unlike in XML, the polytheistic slash has
no effect in HTML. Processing instructions ( 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 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. 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 < (U+003C
LESS-THAN SIGN) character
@@ -226,19 +261,43 @@
/>) cannot be
+ />) cannot be
used for this element./>) must not be used
+ />) must not be used
for the element. The document is non-conforming.base, link, meta,
hr, br, img,
embed, param, area,
col, and input elements.
+
+
+ <script/>script
+ element. Even for an empty script element,
+ there must be an explicit end tag </script>.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/><?...?>) cannot be used.<?...>) cannot be used.
<?...?>),
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.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.<?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.<$0>
- is not allowed in a body element.body element.
body element, appears
@@ -329,7 +402,7 @@
<head>
+ <head>
is not allowed in the head element.<head> in the
@@ -404,7 +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.
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 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
@@ -605,11 +765,35 @@
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.
{@} 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">contentsindex.copyrightlicense.homeindex.previousprev.startfirst.toctoc or topindex.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.
@@ -823,8 +1048,8 @@ <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. @@ -837,6 +1062,23 @@ class="should" level="s">{@}: 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.. 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, @@ -947,34 +1197,56 @@
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.
@@ -987,6 +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.