Contents
This appendix is informative, not normative.
CSS 2.1 is an updated revision of CSS2. The referring style sheet or document's character encoding. Added rule 5 to require falling back to UTF-8. Removed the restriction on using @charset in embedded style sheets. Allowed a BOM to precedechanges between
the @charset rule. Added requirement that @charset rule must beCSS2 specification (see [CSS2]) and this specification fall into
five groups: known errors, typographical
errors, clarifications, changes and additions.
Typographical errors are not listed here.
In addition, this chapter lists the errata
(part 1 and part 2)
that were subsequently applied to CSS 2.1 since it became a
literal '@charset"...";',Candidate Recommendation in July 2007.
This chapter is not a CSS-syntax equivalent. Added requirementcomplete list of changes. Minor editorial
changes and most changes to support for UTF-8 at minimum. Specified that any @charset ruleexamples are also not atlisted here.
New color value: 'orange'
New 'display' value: 'inline-block'
New 'content' values 'none' and precisely defined rules for character encoding detection based on @charset and/or BOM. Specified that UAs must ignore style sheets'normal'. (The values 'none' and
'normal' are equivalent in unknown encodings. C.2.21CSS 2.1, but may have different
functions in CSS3.)
New 'white-space' values: 'pre-wrap' and attribute values RFC 3066 replaces RFC 1766. C.2.22'pre-line'
New 'cursor' value: 'progress'
This new section is non-normative, because, atadded to explain the time of writing, there exist no such formats. C.2.23 Section 5.9 ID selectors Specified how to match elements with two or more ID attributes. C.2.24 Section 5.10 Pseudo-elements and pseudo-classes Removed exceptionmotivation for HTML UAs that allowed them (and only them) to ignore ':first-letter'CSS2.1
and ':first-line'. C.2.25its relation to CSS2.
This section (formerly Section 1.1) has been marked non-normative.
This section (formerly Section 1.2) has been marked non-normative.
This section (formerly unnumbered under 1.3.2) notes that value types are specified
in terms of tokens and :visited UAsthat spaces may return a :visited link to :link status at some point. (This was previously a note, but is now normative.) Addedappear between tokens in values. A note
about privacy concerns with link pseudo classes and allowed UAs to treat :visited as :link. C.2.26explains that spaces are required between some tokens.
This section (formerly unnumbered under 1.3.2) now declares the identifier CMedia line
in ':lang(C)' need not be a valid language code, but it must notproperty definitions to be empty. C.2.27non-normative.
A definition of "first formatted line" to make the rules about whichnew line is added to each property definition specifying what the first line more precise. UAscomputed
values are no longer forbidden from applying more properties than the given list. C.2.28 Section 5.12.2for the :first-letter pseudo-element More precise definition of first letter. Added rules for cases where the first letter is in an inline block or table cell. Added rules for cases when preceding punctuationproperty. (This defines what level of computation is in a different element from the first letter itself. UAs may apply other propertiesdone to
first letters than the given list. Unicode character classes Pia property value before inheritance and Pf added to the definition of punctuation. C.2.29before certain other calculations.)
This section (formerly 1.3.4) now specifies that inheritance can be performed without laying outHTML examples lacking DOCTYPE
declarations are SGML Text Entities conforming to the document.HTML 4.01 Strict DTD [HTML4].
The markup for many examples has been reformulated to either include a DOCTYPE or
conform to this changedefinition.
This section (formerly 1.4) has the effect of allowing (requiring) percentagesbeen updated to be inherited as percentagesreflect contributions to CSS2.1
and affects many other layout calculations throughout the spec. Since computed valuehas been marked non-normative.
Support for user style sheets is now required (in most cases), rather than just recommended.
Support for turning of a property canauthor style sheets is now also be a percentage. In particular, the followingrequired.
Application of CSS properties now inherit the percentage if the specified valueto form controls is a percentage: background-position bottom, left, right, top height, width margin-bottom, margin-left, margin-right, margin-top, min-height, min-width padding-bottom, padding-left, padding-right, padding-top text-indent Note that only 'text-indent' inherits by default, the others only inherit if the 'inherit' keyword is specified. C.2.30 Section 6.4.1 Cascading order Changed suggestion that user be able to turn off author styles to a requirement. C.2.31 Section 6.4.3 Calculating a selector's specificity The "style" attribute now has a higher specificity than any style rule. Pseudo-elementsexplicitly undefined.
Authors are now counted with elements in calculating a a selector's specificity. C.2.32 Section 6.4.4 Precedence of non-CSS presentational hints "Non-CSS presentational hints" no longer exist, with the exception of a small set of attributes in HTML. C.2.33 Section 7.3 Recognized Media Types Added 'speech' media type. Marked "Media" fieldrecommended to treat form control styling capabilities in property descriptions informative. C.2.34UAs
as experimental.
This section informative. Added sound to 'handheld' in media type/media group table.changed 'tactile'to be both 'static' and 'interactive'. C.2.35say that error handling is specified
in most cases.
Added INVALID token and rules for its definition.
An optional hyphen, "-", is now allowed at the containing block's width depends onbeginning of an element with percentage margins, then"ident"
for vendor extensions. (See section 4.1.2.1)
The resulting layoutunderscore character
("_") is undefined in CSS 2.1. C.2.36 Section 8.3.1 Collapsing marginsallowed in identifiers. The definitiondefinitions of "collapsing margins", added "non-empty content"the lexical
macros "nmstart" and "clearance""nmchar" now include it. See also section
4.1.2.1 (Vendor extensions).
The "escape" macro has been modified to allow the parenthetical list of things that prevent consecutive margins from being adjoining. Vertical marginsescaping of elements with 'overflow' other than 'visible' no longer collapseany
character except newlines, form feeds, and hex digits (to avoid
conflict with their in-flow children. Defined how margins collapseUnicode escapes).
Modified "string1" and "string2" macros by defining allowed characters
through an element with adjoining topexcluding disallowed characters. This allows invisible ASCII
characters to be included in a string.
Updated prose about identifiers (second bullet point) to match changes in the tokenization (above).
Excluded null (0x0) character from CSS numerical escapes and indicate that
marginsit is undefined in CSS2.1 what happens if such a character is encountered.
Allowed the use of U+FFFD as a replacement for characters outside the
root element's box do not collapse. More rigorously defined "adjoining"range allowed by Unicode.
CSS is no longer case-insensitive, but case-sensitive with
exceptions. Changed "All CSS style sheets are case-insensitive, except
for margin collapsing . Sixth bullet, second sub-bullet: to findparts that are not under the positioncontrol of CSS" to "All CSS syntax is
case-insensitive within the top border edge, assumeASCII range (i.e., [a-z] and [A-Z] are
equivalent), except for parts that are not under the element has a bottom (rather than top) border. Marginscontrol of relatively positioned elements do sometimes collapse. C.2.37 Section 8.4 Padding properties If the containing block's width depends on an element with percentage padding, thenCSS."
See also the resulting layout is undefinedchange to case-sensitivity of counters in CSS 2.1. C.2.384.3.5.
Defined parsing in bidirectional context Added this new section to specify layoutthe cases of inline boxes when affected by bidi. C.2.41Malformed Declarations,
Unexpected End of Stylesheet, and Unexpected End of String.
Sections 4.3.7 (Angles), 4.3.8 (Times), and 4.3.9 (Frequencies) have been moved to the informative Appendix A.
Added a paragraph to define formatting when an inline box containson heuristics for finding the x-height of a block box. Specified what property values are applied to anonymous boxes. C.2.43 Section 9.2.2.1 Anonymous inline boxes Specified that collapsed white space does not generate anonymous inline boxes. C.2.44font.
Updated URI references to RFC3986.
Changed "Counters are not part of CSS 2.1. Text relatingdenoted by identifiers" to these values has been removed throughout"Counters are
denoted by case-sensitive identifiers" (see also the
specification.change to case-sensitivity in 4.1.3).
Defined the computed valuenumeric values corresponding to color keywords instead
of 'display' as the specified value except for positioned and floating elements and for the root element. The computed value of 'display'referencing HTML4 for these elements is defined in section 9.7 and is slightly different from the definition in CSS2. Conforming HTMLthose values.
UAs are no longernow allowed to ignoreintelligently map colors outside the 'display' property. C.2.46 Section 9.3.1 Choosing a positioning schemegamut
into the 'position' property now applies to all elements, including generated content.gamut instead of simply clipping them into the effectrange of relative positioning on table captions and internal table elements is undefined in CSS 2.1. For fixed positioning, introduced a conflict betweenthe
gamut.
Added this section to recommend that unsupported properties and values be ignored as if they were invalid.
Changed character encoding detection rule 3. See howcome2 to include a BOM and
referred to additional rules below.
Added rule 4 to provide for rationale. Forbid UAs from paginating the contentuse of fixed boxes. UAs are allowedthe referring style sheet
or document's character encoding.
Added rule 5 to treat all values of 'position' as 'static' onrequire falling back to UTF-8.
Removed the root element. C.2.47 Section 9.3.2 Box offsets Defined computed values of 'top', 'right', 'bottom', 'left' basedrestriction on using @charset in embedded style sheets.
Allowed a BOM to precede the value of 'position'. Percentage offsets are no longer undefined for containing blocks without an explicit height. C.2.48 Section 9.4.1 Block formatting contexts Specified@charset rule.
Added requirement that floats, absolutely positioned elements, inline-blocks, table-cells, table-captions, and elements with 'overflow' other than 'visible' establish new block formatting contexts. In the paragraph about the position of@charset rule must be a box's outer edge with respect to its containing block, except boxes that establishliteral '@charset"...";',
not a new block formatting context, as they may become narrower dueCSS-syntax equivalent.
Added requirement to floats. C.2.49 Section 9.4.2 Inline formatting contextsupport for UTF-8 at minimum.
Specified that the effect of 'justify' on the content of a line box doesany @charset rule not affectat the contentsbeginning of inline-table and inline-block boxes. Empty line boxes are now required tothe style sheet
must be treated as zero-heightignored.
Removed note on theoretical problem with @charset problem and ignoredprecisely
defined rules for character encoding detection based on @charset and/or BOM.
Specified that UAs must ignore style sheets in margin collapsing. C.2.50unknown encodings.
of relatively-positioned offsets are, how they affect each other, and what happens when the positioning is overconstrained. (These were not previously defined.) C.2.51BCP 47 replaces RFC 1766.
Class selectors are no longer required to have an explicit width. Floats outsideallowed for other formats than HTML.
Added a note about matching classes in formats with multiple class
attributes per element. The behavior is non-normative, because, at the
time of line boxeswriting, there exist no longer alignsuch formats.
Specified how to the bottom of the preceding block box; it is implied that they are initially alignedmatch elements with their non-floated position. Specified that "If a shortened line box is too small to contain any further content, then it is shifted downward until either it fitstwo or there are nomore floats present." Specified that the border box of a table, block-level replaced element, or element in the normal flowID attributes.
Removed exception for HTML UAs that establishes a new block formatting context must not overlap any floats in the same block formatting context. C.2.52allowed them (and only them) to
ignore ':first-letter' and ':first-line'.
UAs aremay return a :visited link to :link status at some point. (This
was previously a note, but is now normative.)
Added a note about privacy concerns with link pseudo classes and
allowed UAs to treat all values of float:visited as 'none' on:link.
The position ofidentifier C in ':lang(C)' need not be a float whenvalid language code,
but it occurs between two collapsing margins. C.2.53must not be empty.
':first-line' also applies to explain effect of 'clear' on inline elements since CSS1 (but not CSS2 or CSS 2.1) allows 'clear' oninline elements. C.2.54 Section 9.7 Relationships between 'display', 'position',blocks, table captions and
'float' Changed rules to convert 'display' not always to 'block', but to an appropriate block-level display value as given by a mapping table.table cells. Added rule 4 to convert root element's 'display' value accordinga definition of "first formatted line" to make the
mapping. C.2.55 Section 9.9 Layered presentation Specified thatrules about which line is the background and borders of an element that forms a stacking contextfirst line more precise.
UAs are behind all of its descendants, altered stacking context prose to beno longer forbidden from applying more precise, and added a normative Appendix E: Elaborate description of Stacking Contexts to be evenproperties than the
given list.
More precise about the positiondefinition of borders, backgrounds, and content onfirst letter. Added rules for cases
where the z-axis. C.2.56 Section 9.10 Text direction Conforming UAs are now allowed to not support bidirectional text;first letter is in this case they must ignore the 'direction' and 'unicode-bidi' properties. However since applying bidi can havean effect eveninline block or table cell. Added
rules for cases when preceding punctuation is in a document does not contain right-to-left characters,different element
from the first letter itself.
UAs that do support bidi are no longer permitted to notmay apply the algorithm just because the document lacks right-to-left characters. Added a paragraphother properties to define precisely howfirst letters than the given
list.
Unicode bidirectional algorithm appliescharacter classes Pi and Pf added to text inthe CSS formatting modeldefinition of
punctuation.
Redefined "computed value" and created the algorithm. Conforming HTML UAs are no longer exempt from supporting 'direction' and 'unicode-bidi'. C.2.57 Chapter 10 Visual formatting model details Updated prose to useconcept of "used value"
so that inheritance can be performed without laying out the terms "specified", "computed" and "used" as appropriate when referencing values. This affects many calculations indocument.
This section. (See changes to section 6.1 .) C.2.58 Section 10.1 Definition of "containing block" In rule 1, definedchange has the initial containing blockeffect of allowing (requiring) percentages to be inherited
as the viewport for continuous mediapercentages and affects many other layout calculations throughout the page area for paged media. (It was previously undefined.) In rule 2, defined the page area as the containing block for fixed positioned elements in paged media. In rule 4.1, when the containing blockspec.
Since computed value of an absolutely-positioned element is formed by an inline-level element, it isa property can now formed by that element's padding edges, not its content edges.also be a percentage. In
rule 4, changedparticular, the containing block for absolutely positioned elements with only statically positioned elements fromfollowing properties now inherit the root's content box topercentage if the
initial containing block.specified the positioning and breaking behavior of absolutely-positioned elements in paged media. C.2.59 Section 10.2 Contentvalue is a percentage:
Note that ifonly 'text-indent' inherits by default, the containing block's width depends on an element's percentage width, thenothers only
inherit if the resulting layout'inherit' keyword is undefined in CSS 2.1. C.2.60specified.
Changed suggestion that user be able to turn off author styles to a requirement.
The computed values of 'left' and 'right' for"style" attribute now has a higher specificity than any style
rule.
Pseudo-elements are now definedcounted with elements in calculating a
a selector's specificity.
"Non-CSS presentational hints" no longer exist, with the value 'auto' does not always compute to zero.exception
of a small set of attributes in HTML.
Added sections 10.3.9 and 10.3.10 to define calculations for inline blocks. C.2.61'speech' media type.
Marked "Media" field in property descriptions informative.
Marked this section informative.
Added sound to preserve'handheld' in media type/media group table.
Changed 'tactile' to be both 'static' and 'interactive'.
If the replaced content's intrinsic ratio. Sizing of replaced elementscontaining block's width depends on an element with percentage
intrinsic sizes and without intrinsic sizes is now also defined.margins, then the effect of percentage intrinsic widthsresulting layout is nowundefined forin CSS level 2, rather than ignored. C.2.622.1.
In normal flow Specified that a computed total ofthe width, padding,definition of "collapsing margins", added "non-empty content"
and borders that is greater than the containing block width causes auto margins"clearance" to be treated as zero inthe restparenthetical list of the rules. This avoids 'auto' marginsthings that prevent consecutive
margins from being negative on the start edge. C.2.63 Section 10.3.4 Block-level, replacedadjoining.
Vertical margins of elements in normal flow Applied changes to section 10.3.2with 'overflow' other than 'visible' no longer
collapse with their in-flow children.
Defined how margins collapse through an element with adjoining top and
section 10.3.3 to block-level replaced elements in normal flow by referring tobottom margins.
Added that margins of the calculations in those sections. C.2.64 Section 10.3.5 Floating, non-replaced elementsroot element's box do not collapse.
Sixth bullet, second sub-bullet: to this section by referencing it for 'auto' width calculations. C.2.66 Section 10.3.7 Absolutely positioned, non-replaced elements Definedfind the staticposition of an element more precisely. Rewrote constraint rules. The 'direction' property of the containing block of the static position determines which side is clamped to the static position, notthe 'direction' property oftop
border edge, assume the containing blockelement has a bottom (rather than
top) border.
Margins of the absolutelyrelatively positioned element. C.2.67 Section 10.3.8 Absolutely positioned, replacedelements In rule 1, applied sizing rules from section 10.3.2. In rule 2 (formerly rules 2 and 3), referred to new definition of 'static position' indo sometimes
collapse.
If the containing block ofblock's width depends on an element with percentage
padding, then the static position determines which sideresulting layout is clamped to the static position, not the 'direction' property of the containing block of the absolutely positioned element. In rule 4 (formerly rule 5), prevented 'auto' left and right margins in resultingundefined in a negative margin on the start edge. C.2.68CSS 2.1.
'transparent' can now be specified in percentages andindependently for each border side,
on par with <color>.
3D border styles ('groove', 'ridge', 'inset', 'outset') now depend on the
containing block's width dependscorresponding border-color rather than on this element's width, then'color'.
Added this new section to select an arbitrary minimum width. The used widthspecify layout of replaced elements with an intrinsic ratio and both 'width' and 'height' specifiedinline boxes when affected by bidi.
Removed paragraphs about the initial containing block, as 'auto'this is
now calculated accordingdefined differently. (See changes
to section 10.1.)
Added a table designedparagraph to preserve the intrinsic ratio as much as possible within the given constraints. C.2.69 Section 10.5 Content height Removed mention of 'line-height' fordefine formatting when an inline elements since their contentbox height no longer depends on 'line-height'. Percentage heights on absolutely-positioned elements are no longer treated as 'auto' when the containing block's height is not explicitly specified. Addedcontains
a noteblock box.
Specified what property values are applied to explain why this is possible.anonymous boxes.
Specified that a percentage height on the root element is relative to the initial containing block. C.2.70collapsed white space does not generate anonymous
inline boxes.
Changed run-in rules so that a) run-ins that contain blocks become blocks
b) run-ins can only run into sibling blocks and marginsc) run-ins cannot run into
other run-ins.
The 'marker' and 'compact' values of 'top' and 'bottom' forthe 'display' property are
nownot part of CSS 2.1. Text relating to these values has been
removed throughout the specification.
Defined in section 9.3.2 .the computed value 'auto' does not always compute to zero. Added section 10.6.6 to cover cases that are no longer covered underof 'display' as the previous sections. Added section 10.6.7 to define 'auto' heightsspecified value
except for positioned and floating elements and for block formatting context roots. (Unlike other block boxes,the heightroot element.
The computed value of 'display' for these boxes increases to accommodate any normal-flow descendant floats.) C.2.71 Section 10.6.1 Inline, non-replacedelements The height of an inline boxis defined in
section 9.7 and is slightly
different from the definition in CSS2.
Conforming HTML UAs are no longer given byallowed to ignore the 'line-height' property and is now undefined. This'display'
property.
The 'position' property now suggests thatapplies to all elements, including
generated content.
The heighteffect of the box can be basedrelative positioning on the font. C.2.72 Section 10.6.2 Inline replaced elements, block-level replaced elements in normal flow, 'inline-block' replaced elements in normal flowtable captions and floating replacedinternal
table elements The sizing algorithmis undefined in CSS 2.1.
For replaced elements now takes into accountfixed positioning, introduced a conflict between this section
and attemptssection 10.1 rule 3.
See howcome [member-only]
for rationale.
Forbid UAs from paginating the content of fixed boxes.
UAs are allowed to preservetreat all values of 'position' as 'static' on
the replaced content's intrinsic ratio. Sizingroot element.
Defined computed values of replaced elements with'top', 'right', 'bottom', 'left' based
on the value of 'position'.
Percentage intrinsic sizes andoffsets are no longer undefined for containing blocks
without intrinsic sizes is now also defined.an explicit height.
Specified that for inlinefloats, absolutely positioned elements, the margin box is used when calculating the height of the line box. C.2.73 Section 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' This section now only applies to elements whose 'overflow' value computes to 'visible';inline-blocks,
table-cells, table-captions, and elements with other values of'overflow' are discussedother than
'visible' establish new block formatting contexts.
In the paragraph about the position of a box's outer edge with respect
to its containing block, except boxes that establish a new section 10.6.7 ('Auto' heights forblock formatting
context roots). C.2.74context, as they may become narrower due to floats.
Specified that the static positioneffect of an element more precisely. Rewrote constraint rules. C.2.75 Section 10.6.5 Absolutely positioned, replaced elements In rule 1, applied sizing rules from section 10.6.2. C.2.76 Section 10.7 Minimum and maximum heights Percentage min/max heights'justify' on absolutely-positioned elements are no longer treated as '0'/'none' whenthe containing block's height iscontent of a line box
does not explicitly specified. However if the containing block's width depends on an element's percentage width, then the resulting layout is undefined in CSS 2.1.affect the used widthcontents of replaced elements with an intrinsic ratio and both 'width'inline-table and 'height' specified as 'auto' isinline-block boxes.
Empty line boxes are now calculated according to a table designedrequired to preserve the intrinsic ratio as muchbe treated as possible within the given constraints. C.2.77zero-height and
ignored in margin collapsing.
Added rule 4several paragraphs and an example to specify thatexplain exactly what the
heightcomputed values of relatively-positioned offsets are, how they affect
each other, and what happens when the line box must be at least as much as that specified by the 'line-height' property on the this block. C.2.78positioning is overconstrained.
(These were not previously defined.)
Floats are no longer permitted to clip contentrequired to thehave an explicit width.
Floats outside of line box, and are instead asked to render overlappingboxes in document order. 'line-height' set on a blockno longer specifiesalign to the minimal heightbottom of
each inlinethe preceding block box; insteadit specifies the minimal height of each line box. The exact effect of this requirementis expressed in terms of struts; it is affected by vertical-alignment. Adjusted text to reflectimplied that the contentthey are initially
aligned with their non-floated position.
Specified that "If a shortened line box height of an inlineis too small to contain any
further content, then it is shifted downward until either it fits or
there are no longer dictated by the 'line-height' property. Sincemore floats present."
Specified that the contentborder box is now defined by the font and not by the line-height, 'text-top' and 'text-bottom' refer to the content area insteadof the font. Defined 'top' and 'bottom' alignmenta table, block-level replaced element,
or element in terms of aligned subtrees to take into account any protruding descendants. Definedthe baseline of inline tables and inline blocks. C.2.79 Section 11.1 Overflow and clipping Specifiednormal flow that 'overflow' clips toestablishes a new block formatting
context must not overlap any floats in the padding edge. C.2.80same block formatting context.
The 'float' property now may , as opposedalso applies to should .:before/:after and generated
content.
UAs are now requiredallowed to apply the 'overflow' property settreat all values of float as 'none' on the
root elementelement.
Added to rule 4 prose to define the viewport. Additionally, HTML UAs must useposition of a float when it
occurs between two collapsing margins.
Defined clearance to precisely detail the 'overflow' property'clear' property's
effect on margin collapsing and the HTML BODY element instead if the root element's 'overflow' value is 'visible'. Specified placementblock's cleared position.
Added note to explain effect of scrollbar in the box model.'clear' on inline elements since
CSS1 (but not CSS2 or CSS 2.1) allows 'clear' on inline elements.
Changed rules to convert 'display' not always to 'block', but to an appropriate block-level display value as given by a mapping table.
Added rule 4 to convert root element's 'display' value according
to the width of any scrollbars is no longer included inmapping.
Specified that the widthbackground and borders of the containing block. (And consequently, all text in section 10.3an element that subtracts the scrollbar width from the containing block width has been removed.) C.2.81 Section 11.1.2 Clipping: the 'clip' property The 'clip' property now applies onlyforms
a stacking context are behind all of its descendants, altered stacking
context prose to absolutely positioned elements. Furthermore, it appliesbe more precise, and added a normative
Appendix E: Elaborate description of Stacking
Contexts to those elementsbe even when their 'overflow' is 'visible'.more precise about the default valueposition of 'clip', 'auto', now indicates no clipping rather than clipping toborders,
backgrounds, and content on the element's border box. Values of "rect()" should be separated by commas.z-axis.
Conforming UAs are requirednow allowed to not support bidirectional text; in
this syntax, but may also support a space-separated syntaxcase they must ignore the 'direction' and 'unicode-bidi' properties.
However since CSS2 wasapplying bidi can have an effect even when a document
does not clear about this. While CSS2 specified that values of "rect()" give offsets fromcontain right-to-left characters, UAs that do support bidi are
no longer permitted to not apply the respective sides ofalgorithm just because the box, current implementations interpret values with respectdocument
lacks right-to-left characters.
Added a paragraph to define precisely how the top and left edges for all four values (top, right, bottom, and left). This is nowUnicode bidirectional
algorithm applies to text in the specified interpretation. C.2.82 Section 11.2 VisibilityCSS formatting model and how the 'visibility'CSS
'direction' property is now defined to inherit,on blocks maps into the algorithm.
Conforming HTML UAs are no longer exempt from supporting 'direction'
and descendant elements can override an ancestor's hidden visibility. C.2.83'unicode-bidi'.
Updated prose to use the terms "specified", "computed" and lists Moved all discussion of aural rendering"used"
as appropriate when referencing values. This affects many calculations
in this section. (See changes to Appendix A. C.2.84section 12.16.1.)
In rule 1, defined the :before and :after pseudo-elements Removed restrictions on which properties and property values are allowed on ':before'initial
containing block as the viewport for continuous media and ':after' pseudo-elements. C.2.85 Section 12.2the 'content' propertypage
area for paged media. (It was previously undefined.)
In rule 2, defined the initial valuepage area as the containing block for fixed
positioned elements in paged media.
In rule 4.1, when the containing block of 'content'an absolutely-positioned
element is formed by an inline-level element, it is now 'normal',formed by that
element's padding edges, not the empty string. The 'content' property now distinguishes between the empty string, which creates an empty box; and 'normal'/'none', which create no box at all. (There is no distinction between 'normal' and 'none'its content edges.
In level 2.) A UA is now allowed to report a URI that fails to download. Removed recommendation to authors to put rulesrule 4, changed the containing block for absolutely positioned
elements with media-sensitive 'content' properties inside '@media'. Whether '\A' escapes in generatedonly statically positioned elements from the root's
content create line breaks is now subjectbox to the 'white-space' property.initial containing block.
Specified the former section 12.3 on interaction between ':before', ':after'positioning and elements with 'display: compact' or 'display: run-in' has been removed. (The interaction is already fully defined, because generated content consistsbreaking behavior of boxesabsolutely-positioned
elements in paged media.
Declared that if the tree, no different from other boxes.) C.2.86containing block's width depends on an element's
percentage width, then the resulting layout is undefined in CSS 2.1.
The 'content' property Specified that extra 'close-quote'scomputed values of 'left' and 'no-close-quote's (those without a matching 'open-quote' or 'no-open-quote')'right' for are now defined in
section 9.3.2. The value
'auto' does not rendered,always compute to zero.
Added sections 10.3.9 and that neither 'close-quote' nor 'no-close-quote' cause the quoting depth10.3.10 to be negative. C.2.87define calculations for inline blocks.
The sizing algorithm for replaced elements now takes into account and
numbering Defined what a rule with duplicate counters, such as 'counter-reset: section 2 section', means. C.2.88 Section 12.4.1 Nested countersattempts to preserve the replaced content's intrinsic ratio. Sizing of
replaced elements with percentage intrinsic sizes and scopewithout intrinsic
sizes is now also defined.
The scopeeffect of percentage intrinsic widths is now undefined for CSS
level 2, rather than ignored.
Specified that a counter no longer defaults to the whole document, but starts atcomputed total of the first elementwidth, padding, and borders
that usesis greater than the counter. (This affects counters that are used without a prior 'counter-reset'containing block width causes auto margins to
set the scope explicitly.) C.2.89 Section 12.5 Lists Removed textbe treated as zero in section 12.5 (formerly 12.6) relating tothe 'marker' display value. Removedrest of the 'marker-offset' property (and thus formerrules. This avoids 'auto' margins
being negative on the start edge.
Applied changes to section 12.5.1 Lists The list styles 'hebrew', 'armenian', 'georgian', 'cjk-ideographic', 'hiragana', 'katakana', 'hiragana-iroha'10.3.2 and 'katakana-iroha' have been removed due to lack of implementation experience. (They are expectedsection 10.3.3 to returnblock-level
replaced elements in normal flow by referring to the CSS3 Lists module.) Removed the sentence that said that an unknown valuecalculations in
those sections.
Defined computations for 'list-style-type' should cause the value 'decimal''auto' width floats as shrink-to-fit.
(Floats were previously required to be used instead. Instead, normal parsing rules apply and cause the rulehave fixed widths.)
Applied changes to be ignored.section 10.3.2 to this section by referencing
it for 'auto' width calculations.
Defined the sizestatic position of list style markers withoutan intrinsic size is now defined. C.2.91 Chapter 13 Paged mediaelement more precisely.
Rewrote constraint rules.
The 'size', 'marks', and 'page' properties are not part'direction' property of CSS 2.1. C.2.92 Section 13.2.2 Page selectors The requirement for UA's to honor different declarations for :left, :right, and :first pages has been softened to simplify implementations:the page areacontaining block of the :first page may be used for :left and :right pages as well. C.2.93 Section 13.3.1 Page break properties UAs are now only requiredstatic
position determines which side is clamped to applythe page break properties to block-level elements instatic position, not
the normal flow'direction' property of the root element, not to other blocks.However, UAs are now permitted to apply these properties to elements other than block-level elements. Defined treatmentcontaining block of margins, borders, and padding when a page break splits a box.the 'page-break-inside' property no longer inherits. C.2.94absolutely
positioned element.
In rule 1, applied sizing rules from section 10.3.2.
In rule 2 (formerly rules 2 and 3), referred to new definition of 'static position' in section 10.3.7.
Also in rule 2, the 'page-break-inside''direction' property of all ancestorsthe containing block of
the static position determines which side is checked for page-breaking restrictions,clamped to the static
position, not just thatthe 'direction' property of the containing block of the
breakpoint's parent. When dropping restrictions to find a page breaking opportunity, rule A is dropped together with B and D rather than together with C. Removed restriction on breaking withinabsolutely positioned boxes. C.2.95 Section 14.2.1 Background properties For 'background-position',element.
In rule 4 (formerly rule 5), prevented 'auto' left and right margins
in resulting in a negative margin on the restrictionstart edge.
Specified that keywords cannot be combined with percentage or length valuesif the containing block's width is removed. I.e., anegative, the
used value like: '25% top'of a percentage min/max width is now allowed. Also, 'background-position' now applies to all elements, not just to block-levelzero.
Specified that if the min/max width is specified in percentages and
replaced elements. User agents arethe containing block's width depends on this element's width, then the
resulting layout is undefined in CSS 2.1.
The UA is no longer allowed to treat a value of 'fixed' for 'background-attachment' as 'scroll'. Instead they must ignore all such declarations as if 'fixed' wereselect an invalid value.arbitrary minimum width.
The sizeused width of background images withoutreplaced elements with an intrinsic size is now defined. C.2.96 Section 14.3 Gamma correction The contents of this sectionratio and both
'width' and 'height' specified as 'auto' is now calculated according to
a non-normative note. C.2.97 Chapter 15 Fonts The 'font-stretch' and 'font-size-adjust' properties have been removed in CSS 2.1. Font descriptors,table designed to preserve the '@font-face' declaration, and all associated parts ofintrinsic ratio as much as possible
within the font matching algorithm have been removed in CSS 2.1. C.2.98 Section 15.2 Font matching algorithm In thisgiven constraints.
Removed mention of 'line-height' for inline elements since their content box height no longer depends on 'line-height'.
Percentage heights on absolutely-positioned elements are no longer
treated as 'auto' when the font matching algorithm, the UAcontaining block's height is now allowed to use multiple default fallback fonts to find a glyph fornot explicitly
specified. Added a given character. In the per-property rule 2,note to explain why this is possible.
Specified that if there is only a small-caps font ina given family, then that font will be selected by 'normal'. C.2.99 Section 15.2.2 Font familypercentage height on the "missing character" glyphroot element is no longer considered a match forrelative
to the last font in a font set, but is now considered a matchinitial containing block.
The computed values of 'top' and 'bottom' for U+FFFD. Certain punctuation characters when appearing in unquoted font family namesare now required to be escaped. C.2.100defined in
section 15.5 Small-caps9.3.2. The 'font-variant' property's effect isvalue
'auto' does not always compute to zero.
Added section 10.6.6 to cover cases that are no longer restrictedcovered under
the previous sections.
Added section 10.6.7 to bicameral scripts. C.2.101define 'auto' heights for block formatting
context roots. (Unlike other block boxes, the height of these boxes
increases to accommodate any normal-flow descendant floats.)
The computed valueheight of 'font-weight' has been defined more precisely such thatan inline box is no longer given by the 'bolder''line-height'
property and 'lighter' values have an appropriate effect when inheriting through elements with different font-families. C.2.102is now undefined. This section 15.7 Font size Removed suggestionnow suggests that the
height of 1.2 fixed ratio between keyword font sizesthe box can be based on the font.
The 'text-shadow' property is not in CSS 2.1. C.2.104 Section 16.2 Alignmentsizing algorithm for replaced elements now takes into account and
attempts to preserve the initial valuereplaced content's intrinsic ratio. Sizing of
'text-align'replaced elements with percentage intrinsic sizes and without intrinsic
sizes is no longer UA-defined but a nameless valuenow also defined.
Specified that acts as 'left' if 'direction' is 'ltr', 'right' if 'direction' is 'rtl'. The <string> valuefor 'text-align'inline elements, the margin box is not partused when calculating
the height of CSS 2.1. For 'text-align', specified that 'justify' is treated asthe initial valueline box.
This section now only applies to elements whose 'overflow' value computes
to 'visible'; elements with other values of 'white-space' is 'pre' or 'pre-line'. C.2.105'overflow' are discussed in the
new section 16.3.1 Underlining, over lining, striking, and blinking More precisely10.6.7 ('Auto' heights for block formatting context roots).
Defined what boxes are affected by text decorations specifiedthe static position of an element more precisely.
Rewrote constraint rules.
In rule 1, applied sizing rules from section 10.6.2.
Percentage min/max heights on absolutely-positioned elements are no longer treated as '0'/'none' when the containing block's height is not explicitly specified. However if the containing block's width depends on an element's percentage width, then the resulting layout is undefined in CSS 2.1.
The used width of replaced elements with an intrinsic ratio and both
'width' and 'height' specified as 'auto' is now calculated according to
a table designed to preserve the intrinsic ratio as much as possible
within the given element. Specified that underlines, overlines, and line-throughs apply onlyconstraints.
Added rule 4 to text. Specifiedspecify that an underline, overline, or line-through applied across athe height of the line box must be at
a constant vertical position and with a constant thickness across the entire line.least as much as that specified how text decorations are affectedby relative positioning on descendants. User agents are now allowed to recognizethe 'blink' value but not blink, whereas before they were required to ignore'line-height' property on the
'blink' value if they chose not to support blinking text. Added text to allow older UAs to conform tothis block.
UAs are no longer optional. Specified that word spacing affects each space, non-breaking space, and ideographic space left inpermitted to clip content to the text after white space processing rules have been applied. C.2.107 Section 16.5 Capitalization UAsline box, and
are instead asked to render overlapping boxes in document order.
'line-height' set on a block no longer allowed to not transform characters for which there is an appropriate transformation but which are outsidespecifies the minimal height
of Latin-1. C.2.108 Section 16.6 White spaceeach inline box; instead it specifies the 'white-space' property now applies to all elements, not just to block-level elements. "\A"minimal height of each
line box. The exact effect of this requirement is expressed in generatedterms
of struts; it is affected by vertical-alignment.
Adjusted text to reflect that the content box height of an inline
is no longer forces a break for 'normal'dictated by the 'line-height' property.
Since the content box is now defined by the font and 'nowrap' values of 'white-space'. Specified thatnot by the
CSS white space processing model assumes all newlines have been normalized to line feeds. Added section 16.6.1 to precisely define white space handling. Added section 16.6.3line-height, 'text-top' and 'text-bottom' refer to specify handlingthe content area
instead of controlthe font.
Defined 'top' and combining characters. C.2.109 Chapter 17 Tables Moved all discussion'bottom' alignment in terms of aural rendering and related properties to Appendix A. Updated prosealigned subtrees
to usetake into account any protruding descendants.
Defined the terms "specified", "computed"baseline of inline tables and "used" as appropriate when referencing values. (See changes to section 6.1 .) C.2.110inline blocks.
Specified that 'overflow' clips to the padding edge.
'projection' media are no longer allowedpermitted to ignore the table display values on arbitrary HTML elements, only on HTML table elements. C.2.111 Section 17.2.1 Anonymous table objects Changed rules so that internal table elements without an enclosing 'table' or 'inline-table' box generate an anonymous 'inline-table' rather than an anonymous 'table' when inside a "display: inline" parent element. The anonymous table object rulesprint overflowing
content for 'overflow: scroll'. 'print' media now treat anonymous boxesmay, as
equalopposed to elements' boxes. Replaced several instances of the term "element" with "box", removed several instances of "(in the document tree)" and clarified that anonymous boxes generated in earlier rulesshould.
UAs are part of the inputnow required to later rules. Also replacedapply the term "object" with "box", as is used throughout'overflow' property set on the rest ofroot
element to the specification.viewport. Additionally, HTML UAs are no longer exempt from the anonymous box generation rules. C.2.112 Section 17.4 Tables in the visual formatting modelmust use the relationship of'overflow'
property on the caption box, table box, and outer anonymous table box has been changed as follows:HTML BODY element instead if the marginsroot element's
'overflow' value is 'visible'.
Specified placement of scrollbar in the table box now apply to the outer (anonymous) table box that encloses both the tablebox and the caption(s), not to the inner table box.model.
The width of the anonymous boxany scrollbars is now equal tono longer included in the border-boxwidth of
the table box insidecontaining block. (And consequently, all text in section 10.3 that
subtracts the scrollbar width from the containing block width has been
removed.)
The 'clip' property now applies only to absolutely positioned elements.
Furthermore, it instead of adaptingapplies to those elements even when their 'overflow' is
'visible'.
The widths and positionsdefault value of both the table box and its captions. C.2.113 Section 17.4.1 Caption position and alignment'clip', 'auto', now indicates no clipping
rather than clipping to the 'left' and 'right'element's border box.
Values on 'caption-side' have been removed. C.2.114 Section 17.5 Visual layoutof table contents Changed rule 5 in grid layout rules"rect()" should be separated by commas. UAs are
required to allow overlappingsupport this syntax, but may also support a space-separated
syntax since CSS2 was not clear about this.
While CSS2 specified that values of table cells instead"rect()" give offsets from the
respective sides of leaving skipping a gap inthe gridbox, current implementations interpret values
with respect to avoid overlap. C.2.115 Section 17.5.1 Table layersthe top and transparency In point 6, changed 'These "empty" cells are transparent' to: Ifleft edges for all four values
(top, right, bottom, and left). This is now the value of their 'empty-cells'specified
interpretation.
The 'visibility' property is 'hide' these "empty" cells are transparent throughnow defined to inherit, and descendant
elements can override an ancestor's hidden visibility.
Moved all discussion of aural rendering to Appendix A.
Removed restrictions on which properties and property values are allowed on ':before' and ':after' pseudo-elements.
The algorithm described in this sectioninitial value of 'content' is used, tonow 'normal', not the width ofempty
string.
The containing block and'content' property now distinguishes between the content of,empty string,
which creates an empty box; and any CSS properties set on, the table'normal'/'none', which create no box
at all. (There is no distinction between 'normal' and any of its descendants. Added rule 4 to include the column group's width'none' in
the algorithm for determining column widths. C.2.118 Section 17.5.3 Table height algorithms The 'height' property on tableslevel 2.)
A UA is now treated asallowed to report a minimum height; the UA no longer has the option of using 'height'URI that fails to constrain the size of the tabledownload.
Removed recommendation to be smaller than its contents. Percentage heights on table cells, rows, and row groups now computeauthors to 'auto'. The baseline of a cellput rules with media-sensitive
'content' properties inside '@media'.
Whether '\A' escapes in generated content create line breaks is now
defined much more precisely. Definedsubject to the baseline of a row with no baseline-aligned cells. C.2.119 Section 17.5.4 Horizontal alignment in a column'white-space' property.
The <string> value for 'text-align' is not part of CSS 2.1. C.2.120former section 17.6 Borders Several popular browsers assume an initial value for 'border-collapse' of 'separate' rather than 'collapse'12.3 on interaction between ':before', ':after'
and elements with 'display: compact' or exhibit behavior that is close to that value, even if they do not actually implement the CSS table model. 'Separate''display: run-in' has been
removed. (The interaction is now the initial value. C.2.121 Section 17.6.1 The separated borders model Specified the effect of padding on the table element. Specified which partsalready fully defined, because generated
content consists of the table are includedboxes in the width measurement. C.2.122tree, no different from other boxes.)
soSpecified that it is not triggered when the cell includes any child elements, even if theyextra 'close-quote's and 'no-close-quote's (those
without a matching 'open-quote' or 'no-open-quote') are empty.not rendered,
and that neither 'close-quote' nor 'no-close-quote' cause the 'empty-cells' property now hides both bordersquoting
depth to be negative.
Defined what a row when it collapses due to 'empty-cells': it is no longer treatedrule with duplicate counters, such as
"display: none". Instead it is given zero height and its associated border-spacing is eliminated. C.2.123'counter-reset: section 17.6.2 The collapsing border model2 section', means.
The outer halfscope of the table bordersa counter no longer lie indefaults to the margin area. Specified which part ofwhole document,
but starts at the table is consideredfirst element that uses the bordercounter. (This affects
counters that are in the collapsed borders model and how its width is calculated. The edges ofused without a prior 'counter-reset' to set the
boxscope explicitly.)
Removed text in whichsection 12.5 (formerly 12.6) relating to the
table background is painted is, however left explicitly undefined. C.2.124'marker' display value.
Removed the 'marker-offset' property (and thus former section 17.6.2.1 Border conflict resolution Defined in rule 4 what happens when two elements of12.6.1).
The same type conflictlist styles 'hebrew', 'armenian', 'georgian', 'cjk-ideographic',
'hiragana', 'katakana', 'hiragana-iroha' and their borders'katakana-iroha' have
been removed due to lack of implementation experience. (They are
expected to return in the same widthCSS3 Lists module.)
Removed the sentence that said that an unknown value for
'list-style-type' should cause the value 'decimal' to be used instead.
Instead, normal parsing rules apply and style. C.2.125 Section 18.1 Cursors:cause the 'cursor' propertyrule to be
ignored.
The size of cursorslist style markers without an intrinsic size is now
defined.
The 'size', 'marks', and 'page' properties are not part of
outline with respectCSS 2.1.
The requirement for UA's to honor different declarations for
:left, :right, and :first pages has been softened to simplify
implementations: the border edge is now only suggested, not required. Conformantpage area of the :first page may be used
for :left and :right pages as well.
UAs are now allowedonly required to ignoreapply the 'invert' value.page break properties
to block-level elements in such UAs the initial value of 'outline-color' isthe valuenormal flow of the 'color' property. C.2.127 Chapter 12 Generated content, automatic numbering, and lists The 'marker' value for 'display' does not exist in CSS 2.1 C.2.128 Appendix A. Aural style sheets Chapter 19 on aural style sheets has become appendix A and isroot element,
not normative in CSS 2.1. Related units (deg, grad, rad, ms, s, Hz, kHz)to other blocks.However, UAs are also movednow permitted to this appendix, as is the 'speak-header' property from the "tables" chapter andapply these
properties to elements other notes on aural table rendering. The 'aural' media type is deprecated in favorthan block-level elements.
Defined treatment of the new 'speech' media type. C.2.129 Appendixmargins, borders, and padding when a page
break splits a box.
The 'page-break-inside' property no longer inherits.
The initial value'page-break-inside' property of 'pause-before' and 'pause-after' to be 0 insteadall ancestors is checked
for page-breaking restrictions, not just that of UA-defined. A note has been added to this section (formerly 19.4) aboutthe change in position and behavior of pauses in CSS3 Speech comparedbreakpoint's
parent.
When dropping restrictions to this appendix. C.2.130 Appendixfind a Section 6 Cue properties This section (formerly Section 19.5) now specifies the placement of cues and pausespage breaking opportunity,
rule A is dropped together with respect to the :beforeB and :after pseudo-elements. C.2.131 Appendix AD rather than together with C.
Removed restriction on breaking within absolutely positioned boxes.
For 'background-position', the restriction that keywords 'mix' and 'repeat' maycannot
be combined with percentage or length values is removed. I.e., a
value like: '25% top' is now appear in either order. C.2.132 Appendix B Bibliography Various references in Appendix B (formerly Appendix E) have been updated as appropriate. Switched [CSS1] from Normative to Informative. Updated URI reference from [RFC1808] and the draft-fielding-uri-syntax-01.txt to [RFC3986]. Updated HTTP reference from [RFC2068] to [RFC2616]. Removed normative references to [IANA] and [ICC32]. Added normative referencesallowed. Also, 'background-position'
now applies to [ICC42], [RFC3986], [RFC2070], [UAAG10]. Added informative referencesall elements, not just to CSS2, CSS3 Color, CSS3 Lists, Selectors, CSS3 Speech, DOM 3 Core, MathML 2, P3P, RFC1630, SVG 1.1, XHTML 1, XML ID,block-level and XML Namespaces. Removed informative references to [ISO10179] (DSSSL), [INFINIFONT], [ISO9899] (C), [MONOTYPE], [NEGOT], [OPENTYPE], [PANOSE], [PANOSE2], [POSTSCRIPT], [RFC1866] (HTML 2), [RFC1942] (HTML Tables), [TRUETYPEGX], [W3CStyle]. Updated language tags references from [RFC1766]replaced
elements.
User agents are no longer allowed to [3066]. C.2.133 Other The former informative appendix C, "Implementation and performance notes for fonts," is left out of CSS 2.1. C.3 Errors C.3.1 Shorthand properties Shorthand properties taketreat a list of subproperty values or thevalue 'inherit'. One cannot mix 'inherit' with other subproperty valuesof 'fixed'
for 'background-attachment' as it would not be possible to specify the subproperty to which 'inherit' applied.'scroll'. Instead they must ignore
all such declarations as if 'fixed' were an invalid value.
The definitionssize of a numberbackground images without an intrinsic size is now
defined.
The contents of shorthand properties did not enforcethis rule: 'border-top', 'border-right', 'border-bottom', 'border-left', 'border', 'background', 'font', 'list-style', 'cue',section is now a non-normative note.
The 'font-stretch' and 'outline'. C.3.2 Applies to'font-size-adjust' properties have
been removed in CSS 2.1.
Font descriptors, the "applies to" line'@font-face' declaration, and all
associated parts of many property definitions hasthe font matching algorithm have been
made more accurate by excluding or including table display types where appropriate. C.3.3removed in CSS 2.1.
In this section 4.1.6 on strings, which must have(previously 15.5), in step 5 (previously 8)
of the font matching single or double quotes around them. Removed "A-Z" fromalgorithm, the "nmchar" token: as CSSUA is case insensitive anyway, it was redundant. Corrected "unicode" macronow allowed to treat CRLF asuse
multiple default fallback fonts to find a singleglyph for a given
character.
Corrected "block" production to allow white space between declarations.In the per-property rule for "any" (in the core syntax), corrected "FUNCTION" to "FUNCTION any* ')'". C.3.4 Section 4.1.3 Characters and case Corrected third paragraph to say2, specified that an '@import' rule canif there is only
a small-caps font in a given family, then that font will be
precededselected by an '@charset' rule or other '@import' rules. C.3.5 Section 4.3 (Double sign problem) Several values described in subsections of this section incorrectly allowed two "+" or "-" signs at their beginnings. C.3.6'normal'.
The suggested reference pixel to be based on"missing character" glyph is no longer considered a 96 dpi device, not 90 dpi.match
for the visual angle is thus about 0.0213 degrees instead of 0.0227, andlast font in a pixel at arm's lengthfont set, but is about 0.26 mm instead of 0.28 Corrected last sentencenow considered a match
for U+FFFD.
Certain punctuation characters when appearing in unquoted font
family names are now required to referbe escaped.
The 'font-variant' property's effect is no longer restricted to
a unsupported used length, not an unsupported specified length. C.3.7bicameral scripts.
The computed value of <percentage>. (<number> already'font-weight' has a sign.) C.3.8 Section 4.3.4 URLs and URIsbeen defined escaping requirements in terms of the URI token somore
precisely such that no escaping requirements are missing fromthe prose. Included invalid URIs in last paragraph about URI error handling. C.3.9'bolder' and 'lighter' values have an
appropriate effect when inheriting through elements with
different font-families.
Removed suggestion of counter()1.2 fixed ratio between keyword font
sizes in favor of notes recommending a variable ratio and counters() notationa
smallest font-size no less than 9 pixels per EM unit.
Added table mapping CSS font-size keywords to allow white space between tokens. C.3.10 Section 4.3.6 Colors DeletedHTML font size numbers.
The comments about range restriction after'text-shadow' property is not in CSS 2.1.
The following examples: em { color: rgb(255,0,0) } em { color: rgb(100%, 0%, 0%) } C.3.11 Section 4.3.7 Strings (Formerly section 4.3.10) Corrected text to allow all formsinitial value of Unicode escapes'text-align' is no longer UA-defined but
a nameless value that acts as 'left' if 'direction' is 'ltr',
'right' if 'direction' is 'rtl'.
The <string> value for U+000A,'text-align' is not just the "\A" form,part of
CSS 2.1.
For including newlines in strings. C.3.12'text-align', specified that 'justify' is treated as the initial
value when computed value of 'white-space' is 'pre' or 'pre-line'.
More precisely defined what boxes are affected by text decorations specified on a given element.
Specified that the ':lang()' pseudo-class can alsounderlines, overlines, and line-throughs apply only to
text.
Specified that an underline, overline, or line-through applied across
a line must be deduced from the document in some cases. C.3.13 Section 6.4at a constant vertical position and with a constant
thickness across the cascade Removed paragraph about imported style sheets being overriddenentire line.
Specified how text decorations are affected by rules in the importing style sheet: imported style rules followrelative positioning
on descendants.
User agents are now allowed to recognize the cascade as specified in 6.4.1 Cascading order , exactly as if'blink' value but not
blink, whereas before they were inserted in place ofrequired to ignore the @import rule. C.3.14'blink' value
if they chose not to support blinking text.
Added text to allow older UAs to conform to this section 8.1 Box Dimensionsif they
follow CSS2's 'text-decoration' requirements but not the definition of "content edge" has been changed to depend on 'width'additional
requirements in CSS2.1.
Support for the definitionvarious values of "padding edge", deleted'letter-spacing' and 'word-spacing'
is no longer optional.
Specified that word spacing affects each space, non-breaking space,
and ideographic space left in the sentence "The padding edgetext after white space processing
rules have been applied.
UAs are no longer allowed to not transform characters for which there
is an appropriate transformation but which are outside of a box definesLatin-1.
The edges'white-space' property now applies to all elements, not just
to block-level elements.
"\A" in generated content no longer forces a break for 'normal' and 'nowrap' values of 'white-space'.
Specified that the containing block established by the box." For information about containing blocks, consultCSS white space processing model assumes all
newlines have been normalized to line feeds.
Added section 10.1 . C.3.1516.6.1 to precisely define
white space handling.
Added section 8.2 Example16.6.3 to specify handling
of margins, padding,control and borders The colors in the example HTML did not match the colors in the image. C.3.16 Section 8.5.4 Border shorthandcombining characters.
Moved all discussion of aural rendering and related properties
Changed various border shorthands' syntax definitionsto Appendix A.
Updated prose to use the <border-width>, <border-style>terms "specified", "computed" and <'border-top-color'> value types"used"
as appropriate. C.3.17appropriate when referencing values. (See changes
to section 9.2.1 Block-level elements and block boxes Excepted6.1.)
Defined handling of "position: static", added 'right'multiple 'table-header-group' and 'bottom''table-footer-group'
elements.
UAs are no longer allowed to ignore the sentence saying that 'top' and 'left' do not apply. C.3.19table display values
on arbitrary HTML elements, only on HTML table elements.
Changed rules so that internal table elements without an enclosing
'table' or 'inline-table' box offsetsgenerate an anonymous 'inline-table'
rather than an anonymous 'table' when inside a "display: inline"
parent element.
The properties 'top', 'right', 'bottom', and 'left', incorrectly referredanonymous table object rules now treat anonymous boxes as equal
to offsetselements' boxes. Replaced several instances of the term "element" with
respect to a box's content edge."box", removed several instances of "(in the proper edge isdocument tree)" and clarified
that anonymous boxes generated in earlier rules are part of the margin edge. Thus, for 'top',input to
later rules. Also replaced the description now reads: "This property specifies how far a box's top margin edgeterm "object" with "box", as is offset belowused
throughout the top edgerest of the box's containing block." Corrected text under property definitions to say that for relatively-positioned elements, 'top', 'right', 'bottom', and 'left' define the offsetspecification.
HTML UAs are no longer exempt from the box's positionanonymous box generation rules.
The edgesrelationship of the containing block. (The previous definition conflicted with that was further down; since that text is now redundant, itcaption box, table box, and outer anonymous
table box has been removed.) C.3.20 Section 9.4.1 Block formatting contexts In paragraph about relationshipchanged as follows:
The float Correct "Applies to" line'left' and prose'right' values on 'caption-side' have been removed.
Changed rule 5 in grid layout rules to say thatallow overlapping of
table cells instead of leaving skipping a gap in the 'float' property can be set for any element but only appliesgrid to
elements thatavoid overlap.
In point 6, changed 'These "empty" cells are not absolutely positioned. C.3.25transparent' to:
If the value of their 'empty-cells' property is 'hide' these "empty" cells are transparent through the cell, row, row group, column, and column group backgrounds, letting the table background show through.
Specified for any element, it only applies to block-level elements. C.3.26 Section 9.6 Absolute positioning Corrected sentencethat said absolutely positioned boxes establish a new containing block for absolutely positioned descendants to exceptin fixed positioned descendants. C.3.27 Section 9.7 Relationships between 'display', 'position', and 'float'table layout, extra columns in rule 1, corrected "user agentsrows
after the first must ignore 'position' and 'float" to "'position' and 'float' donot apply". C.3.28be rendered.
Restricted inputs to say that "columns arethe table layout algorithm for 'table-layout: auto',
whether or not the ancestorsalgorithm described in this section is used, to the
width of the cells incontaining block and the document tree" rather than saying "columns do not exist incontent of, and any CSS properties
set on, the document tree". Added table cells,table captions,and inline blocks alongside block-level elements in description of 'bidi-override' value. Also corrected the prose to handle anonymous child blocks. Updated mentionany of Unicode's embedding limit from 15its descendants.
Added rule 4 to 61. C.3.29 Section 10.1 Definition of "containing block" Included table cells (and inline blocks) together with block-level elementsinclude the column group's width in rule 2 definingthe containing block of non-absolutely-positioned elements. C.3.30algorithm
for determining column widths.
The last sentence'height' property on tables is now treated as a minimum
height; the UA no longer has the option of using 'height' to
constrain the paragraph followingsize of the equation ("Iftable to be smaller than its contents.
The valuebaseline of 'direction'a cell is 'ltr', this happens to 'margin-left' instead") substituted 'rtl' for 'ltr'. C.3.31now defined much more precisely.
Defined the baseline of a row with no baseline-aligned cells.
The initial<string> value for 'min-width''text-align' is now '0'not part of
CSS 2.1.
Several popular browsers assume an initial value for
'border-collapse' of 'separate' rather than UA-dependent. Corrected "applies to" exception for both 'min-width' and 'max-width' from "table elements" to "table rows and row groups". Specified'collapse' or exhibit
behavior that negative values for 'min-width' and 'max-width' are illegal. C.3.32 Section 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computesis close to 'visible' Addedthat 'auto' height also depends on whethervalue, even if they do not actually
implement the element has padding or borders, as these influence margin-collapsing behavior. Added text to correctly account for margin collapsing behavior. C.3.33CSS table model. 'Separate' is now the initial value.
Specified that negative values for 'min-height' and 'max-height'the effect of padding on the table element.
Specified which parts of the table are illegal. C.3.34included in the width
measurement.
Refined definition of "empty" when used as a DIV element containing a BLOCKQUOTE containing another DIV was not rendered correctly.condition for the
first style rule applied to both DIVs,'empty-cells' property so that it is not triggered when the second DIV box should have been rendered with a red border as well.cell
includes any child elements, even if they are empty.
The second DIV has'empty-cells' property now been changed to a CITE, which doeshides both borders and backgrounds,
not havejust borders.
Changed behavior of a red border. C.3.35 Section 11.1.2 Clipping: the 'clip' property Corrected "rect (<top> <right> <bottom> <left>)"row when it collapses due to "rect(<top>, <right>, <bottom>, <left>)". C.3.36'empty-cells':
it is no longer treated as "display: none". Instead it is given zero
height and its associated border-spacing is eliminated.
The outer half of 'visibility' to 'visible'. C.3.37 Section 12.4.2 Counter stylesthe example usedtable borders no longer lie in the style 'hebrew',margin area.
Specified which does not exist in CSS level 2. Changed to 'lower-greek'. C.3.38 Section 12.6.2 Lists Underpart of the 'list-style' property,table is considered the example: ul > ul { list-style: circle outside } /* Any UL child of a UL */ could never match valid HTML markup (since a UL element cannot be a child of another UL element). An LI has been insertedborder are
in between. C.3.39 Section 14.2the background Second sentence: "In termscollapsed borders model and how its width is calculated.
The edges of the box model, 'background' refers toin which the table background of the content and the padding areas" now also mentions the border area. (See also errata tois painted
is, however left explicitly undefined.
Defined in termsrule 4 what happens when two elements of the box model, "background" refers to the background ofsame
type conflict and their borders have the content, paddingsame width and border areas. C.3.40style.
The background image has intrinsic sizes specified in percentages or nosize of cursors without an intrinsic size. Under 'background-repeat', the sentence "All tiling covers the content and padding areas [...]" has been correctedsize is now defined.
Position of outline with respect to "All tiling coversthe content, padding andborder areas [...]". Under 'background-attachment', the value 'scroll'edge is definednow
only suggested, not required.
Conformant UAs are now allowed to scroll with the "containing block" rather than with the "document". Alsoignore the sentence "Even if'invert' value.
In such UAs the imageinitial value of 'outline-color' is fixed [...] background or padding areathe value of
the element" has been corrected to Even if'color' property.
The image is fixed, it is still only visible when it is'marker' value for 'display' does not exist in the background, padding or border area of the element. C.3.41 Section 15.2 Font matching algorithmCSS 2.1
Chapter 19 on aural style sheets has become appendix A and is not
normative in bullet 2, changed "the UA uses the 'font-family' descriptor" to "the UA uses the 'font-family' property". C.3.42 Section 15.7 Font size The statement "Negative valuesCSS 2.1. Related units (deg, grad, rad, ms, s, Hz,
kHz) are not allowed" for 'font-size' now appliesalso moved to percentages as wellthis appendix, as lengths. C.3.43 Section 16.1 Indentation Corrected 'text-indent' to apply tois the 'speak-header'
property from the "tables" chapter and other notes on aural table
cells (and inline blocks) as well as block-level elements. C.3.44rendering. The 'aural' media type is deprecated in favor of the new
'speech' media type.
Changed prose aboutthe effectinitial value of 'justify''pause-before' and 'pause-after' to
be less correct. Corrected the0 instead of UA-defined.
A note has been added to say that justification is also dependent on the script, not just the language, of the text. C.3.45this section 17.2(formerly 19.4) about the CSS table modelchange
in the definitionposition and behavior of table-header-group , changed "footer" to "header"pauses in "Print user agents may repeat footer rows on each page spanned by a table." C.3.46 Section 17.2.1 Anonymous table objects Added 'table-header-group' and 'table-footer-group' alongside mentions of 'table-row-group' where missing. Corrected 'caption' to 'table-caption'. Added missing rule (#3) for 'table-column' boxes. Added 'table-caption' and 'table-column-group'CSS3 Speech compared to list of boxes requiringthis appendix.
This section 17.4 Tables in(formerly Section 19.5) now specifies the visual formatting model Specified handlingplacement
of multiple caption boxes. Specified that the anonymous outer table box is a 'block' box if the table is block-levelcues and an 'inline-block' box if the table is inline-level but that the anonymous outer table box cannot accept run-ins. C.3.48 Section 17.5 Visual layout of table contents Correct text that said all internal table elements have padding; changepauses with respect to say that of these only table cells have padding.the following note: Note. Table cells may be relatively and absolutely positioned, but this is not recommended: positioning:before and floating remove:after pseudo-elements.
The flow, affecting table alignment. has been amended as follows: Note. Table cells may be positioned, but this is not recommended: absolutekeywords 'mix' and fixed positioning, as well'repeat' may now appear in either order.
Various references in Appendix B (formerly Appendix E) have been
updated as floating, remove a boxappropriate.
Switched [CSS1] from Normative to Informative.
Updated URI reference from [RFC1808] and the flow, affecting table size. C.3.49 Section 17.5.1 Table layers and transparency The rowsdraft-fielding-uri-syntax-01.txt
to [RFC3986].
Updated HTTP reference from [RFC2068] to [RFC2616].
Removed normative references to [IANA] and columns only cover the whole table in the collapsed borders model, not in the separated borders model. The points[ICC32].
Added normative references to [ICC42], [RFC3986], [RFC2070], [UAAG10].
Added informative references to CSS2, CSS3 Color, CSS3 Lists,
Selectors, CSS3 Speech, DOM 3 Core, MathML 2, 3, 4P3P, RFC1630, SVG 1.1,
XHTML 1, XML ID, and 5 have been correctedXML Namespaces.
Removed informative references to define the area covered by rows, columns, row groups and column groups and thus[ISO10179] (DSSSL), [INFINIFONT],
[ISO9899] (C), [MONOTYPE], [NEGOT], [OPENTYPE], [PANOSE], [PANOSE2],
[POSTSCRIPT], [RFC1866] (HTML 2), [RFC1942] (HTML Tables), [TRUETYPEGX],
[W3CStyle].
Updated language tags references from [RFC1766] to [BCP47].
The positioningformer informative appendix C, "Implementation and
paintingperformance notes for fonts," is left out of backgrounds on those elements. Specify the handlingCSS 2.1.
Shorthand properties take a list of "missing cells". C.3.50 Section 17.6.1 The separated borders model Insubproperty values or
the image, changed "cell-spacing"value 'inherit'. One cannot mix 'inherit' with other subproperty
values as it would not be possible to "border-spacing". C.3.51 Section 18.2 System Colors For the 'ButtonHighlight' value, changedspecify the description from "Dark shadow" to "Highlight color". C.3.52 Section E.2 Painting order Changed "but any descendants which actually create a new stacking context"subproperty to "but any positioned descendants and descendantswhich
actually create'inherit' applied. The definitions of a new stacking context" (3 times).number of shorthand properties
did not enforce this change also occurred once in section 9.5 (Floats)rule: 'border-top', 'border-right',
'border-bottom', 'border-left', 'border', 'background', 'font',
'list-style', 'cue', and once in section section 9.9 (Layered presentation). C.4 Clarifications C.4.1 Section 2.1 A brief CSS 2.1 tutorial for HTML This section has been marked non-normative. C.4.2 Section 2.2 A brief CSS 2.1 tutorial for XML This section has been marked non-normative. Added a statement about case-sensitivity of selectors for XML. The specification for the XML style sheet PI was written after CSS2 was finalized.'outline'.
The first"applies to" line of the full XML example should not have been be <?XML:stylesheet type="text/css" href="bach.css"?> , but <?xml-stylesheet type="text/css" href="bach.css"?> C.4.3 Section 2.3 The CSS 2.1 processing model This sectionmany property definitions has been marked non-normative. C.4.4made more
accurate by excluding or including table display types where appropriate.
DELIM should not have included single or double quote. Refer also
to clarify that the deprecated/non-deprecated status of a feature is distinctsection 4.1.6 on strings, which must have matching single or
double quotes around them.
Removed "A-Z" from its normative/non-normative status. Under 'document language' clarified that CSS only describesthe presentation of"nmchar" token: as CSS is case insensitive
anyway, it was redundant.
Corrected "unicode" macro to treat CRLF as a document language, and has no effect on its semantics. Changed definition of 'replaced element'single character.
Corrected "block" production to "an element whose content is outsideallow white space between declarations.
In the scope ofrule for "any" (in the CSS formatting model" and added further clarifying text. This clarifies that e.g., SVG images embedded incore syntax), corrected "FUNCTION"
to "FUNCTION any* ')'".
Corrected third paragraph to say that an XML document are also considered replaced elements, not just those linked in from'@import' rule can only be
preceded by an outside file. Also changed definition'@charset' rule or other '@import' rules.
Several values described in subsections of 'rendered content' to be consistent withthis clarification. Added under "Intrinsic dimension" that raster images without reliable resolution information are assumed to have a size of 1 px unit per image source pixel. Added definition for 'ignore'. Added definition for 'HTML user agent'. Added definition for 'property'. C.4.5section
4.1 Syntax Moved definitionsincorrectly allowed two "+" or "-" signs at their beginnings.
Fixed double sign error in definition of "immediately before" and "immediately after" forward so they apply to<length>.
(<number> already has a sign.)
Corrected the whole Syntax section. Added sections 4.1.2.1 and 4.1.2.2suggested reference pixel to defined vendor-specific extensions. C.4.6 Section 4.1.1 Tokenization Clarified that input that cannotbe parsed according tobased on a
96 dpi device, not 90 dpi. The core syntaxvisual angle is
ignored according to the rules for handling parsing errors. Clarified that input that cannot be tokenized or parsed has no meaning in CSS2.1. C.4.7 Section 4.1.3 Charactersthus about 0.0213 degrees instead of 0.0227, and case Clarified that whena CRLF pair terminates an escape sequence, the pairpixel
at arm's length is treated as a single white space character asabout 0.26 mm instead of 0.28
Corrected in the tokenization rules. Replaced "[a-z0-9]" by "[a-zA-Z0-9]" aslast sentence to refer to a unsupported used
length, not an extra reminderunsupported specified length.
Fixed double sign error in definition of <percentage>. (<number> already has a sign.)
Defined escaping requirements in terms of the URI token so that
CSS identifiersno escaping requirements are case-insensitive. C.4.8missing from the prose.
Included invalid URIs in last paragraph about URI error handling.
Corrected syntax of counter() and selectors Replacedcounters() notation to allow white space
between tokens.
Deleted the term "{}-block" with "declaration block". C.4.9comments about range
restriction after the following examples:
em { color: rgb(255,0,0) }
em { color: rgb(100%, 0%, 0%) }
(Formerly section 4.3.10) Corrected text to allow all property:value combinations and @-keywords that do not contain an identifier beginning with dash or underscore are reserved by CSSforms of Unicode
escapes for future use. Clarified that when something inside an at-rule is ignored because it is invalid, this doesU+000A, not makejust the entire at-rule invalid. Referenced section 4.1.7"\A" form, for parsing invalid bits inside declaration blocks. C.4.10including newlines in
strings.
In the second bullet, added that do not allow them causethe declaration to':lang()' pseudo-class can also
be ignored. C.4.12 Section 4.3.4 URLs and URIs Reduced unnecessary discussion of what a URI is. C.4.13 Section 5.1 Pattern matching Added note about terminology change ("simple selector") between CSS2 and CSS3. C.4.14 Section 5.7 Adjacent sibling selectors Clarified that text nodes and comments do not affect whether a sibling selector matches. C.4.15 Section 5.8.1 Matching attributes and attribute values Clarified ~= and |= by using the definitionsdeduced from the Selectors module. C.4.16 Section 5.8.2 Default attribute valuesdocument in DTDs Clarified that rulessome cases.
Removed paragraph about default attribute values areimported style sheets being overridden by
rules in the same, whetherimporting style sheet: imported style rules follow the
default iscascade as specified in a DTD or by other means. C.4.17 Section 5.9 ID selectors Added a note that it depends on6.4.1
Cascading order, exactly as if they were inserted in place of the
document format which attributes are ID attributes. C.4.18@import rule.
The dynamic pseudo-classes: :hover, :active,definition of "content edge" has been changed to depend on 'width'
and :focus Clarified that CSS 2.1 does not define if'height' rather than directly on 'rendered content'.
From the parentdefinition of an element that matches ':active' or ':hover' itself also matches ':active' or ':hover'. Added note that, in CSS1, ':active' only applies to links. C.4.19 Section 5.11.4"padding edge", deleted the language pseudo-class: :lang Addedsentence "The
padding edge of a note to showbox defines the differences between ':lang(xx)' and '[lang=xx]'. C.4.20 Section 5.12.2edges of the :first-letter pseudo-element Clarified that digits can also be first letter. C.4.21containing block
established by the box." For information about containing
blocks, consult
Section 6.2 Inheritance Clarified that computed values are inherited (not specified values)10.1.
The specified value oncolors in the inheritor. Removed discussion of "default" styles for a document. C.4.22example HTML did not match the colors in the
image.
Changed various border shorthands' syntax definitions to use the
'inherit'<border-width>, <border-style> and <'border-top-color'>
value Clarify that 'inherit' can be used on properties that are not normally inheritedtypes as appropriate.
Excepted table elements from second paragraph about principal block boxes and their contents.
Corrected sentence to say "either only block boxes or only inline
boxes" instead of assigning the property's initial value. C.4.23"only block boxes".
In the @import rule Except @charset fromdefinition of "position: static", added 'right' and 'bottom'
to the statementsentence saying that @imports must precede all other rules. C.4.24'top' and 'left' do not apply.
The Cascade Obfuscated note about system settingsproperties 'top', 'right', 'bottom', and UA limitations. C.4.25 Section 6.4.1 Cascading order Various editorial changes'left', incorrectly
referred to offsets with respect to clarify sort order. C.4.26 Section 6.4.3 Calculating a selector's specificity Addeda note:box's content edge. The specificityproper edge
is based only on the form ofthe selector. In particular, a selector ofmargin edge. Thus, for 'top', the form " [id=p33] " is counted as an attribute selector (a=0, b=1, c=0), even if the id attributedescription now reads:
"This property specifies how far a box's top margin edge is defined as an "ID" in the source document's DTD. C.4.27 Section 7.2.1offset
below the @media rule Clarify that Style rules outsidetop edge of @media rules apply to the same media types thatthe style sheet itself applies to. C.4.28 Section 7.3 Recognized media types Addedbox's containing block."
Corrected text under property definitions to clarifysay that media types are mutually exclusive, but a UA can render simultaneously to canvases with different media types. C.4.29 Section 7.3.1 Media groups Split "aural" media group into "audio"for
relatively-positioned elements, 'top', 'right', 'bottom', and "speech". C.4.30 Section 8.1 Box dimensions'left'
define the terms "content box", "padding box", "border box", and "margin box" have been defined. Border backgrounds areoffset from the box's position in the normal flow, not
specified by border properties. Changedfrom the last paragraphedges of 8.1 to:the background stylecontaining block. (The previous definition
conflicted with that was further down; since that text is now
redundant, it has been removed.)
In paragraph about relationship of a box's outer edges to its
containing block's edges, corrected parenthetical to say that
line boxes, not the content, padding, and border areascontent area, may shrink due
to floats.
Added "and the presence of floats" to "The width of a line box is
specifieddetermined by a containing block".
In the 'background' property of the generating element. Margin backgroundsfirst paragraph, added "or floated" to the phrase "laid out
according to the normal flow" as floated elements can be relatively
positioned but are always transparent. Removed definitionnot part of "box width" and "height". C.4.31the normal flow.
Corrected sentence about not enough horizontal room for the float
to notesay that vertical margins haveit is shifted downward until either it fits or there
are no effect on non-replaced inline elements. C.4.32more floats present.
Correct "Applies to" line and prose to say that the first bullet of the explanation of vertical collapsing of margins: Note. Adjoining boxes may'float' property
can be generated byset for any element but only applies to elements that are not
related as siblings or ancestors. Emphasized that floating elements' margins do not collapse even between a float and its in-flow children. Emphasized thatabsolutely positioned elements' margins do not collapse even between the positioned element and its in-flow children. C.4.33positioned.
Removed sentence saying that all four border widths are set'clear' may only be specified for
block-level elements: it can be specified for any element, it only
applies to zero. C.4.34block-level elements.
Corrected sentence "When the viewport is smaller than the ..., the user agent should offer a scrolling mechanism" to use "area of the canvas on which the document is rendered" instead of "document's initial containing block". C.4.35 Section 9.2.4 The 'display' property Clarifiedthat 'display: none' also applies to non-visual media. C.4.36 Section 9.3.1 Choosingsaid absolutely positioned boxes establish
a positioning scheme Clarified that the margins ofnew containing block for absolutely positioned descendants to
except fixed positioned boxesdescendants.
In rule 1, corrected "user agents must ignore 'position' and 'float"
to "'position' and 'float' do not collapse with any other margins. Clarified that in print media fixed boxes are rendered on every page. C.4.37apply".
Corrected note about 'direction' on table column elements to say
that negative lengths and percentages"columns are allowed as values of 'top', 'right', 'bottom', and 'left'. Added "For replaced elements, the effect of this value depends only onnot the intrinsic dimensionsancestors of the replaced content. Seecells in the sections ondocument tree"
rather than saying "columns do not exist in the widthdocument tree".
Added table cells, table captions, and height of absolutely positioned, replacedinline blocks alongside
block-level elements for details." toin description of 'bidi-override' value. Also
corrected the definitionprose to handle anonymous child blocks.
Updated mention of 'auto' because that's not what chapter 10 says at all. C.4.38Unicode's embedding limit from 15 to 61.
Included table cells (and inline formatting context Clarified that 'justify' stretches "spaces and wordsblocks) together with block-level elements
in inline boxes"; previous text simply said that it stretches "inline boxes". The statement "When an inline box is split, margins, borders, and padding have no visual effect where the split occurs." has been generalized. Margins, borders, and padding have no visual effect where one or more splits occur. Clarified that an inline box that exceeds the width of a line box and cannot be split therefore overflowsrule 2 defining the line box. Removed sentence about formattingcontaining block of margins, borders, and padding for split inline boxes not being fully defined when affected by bidi as that situation is now defined in section 8.6 . C.4.39non-absolutely-positioned elements.
In the creationlast sentence of scrollbars. Relatively positioned boxes do not always establish new containing blocks. Changedthe secondparagraph to refer tofollowing the equation
("If the value of 'direction' is 'ltr', this happens to
'margin-left' instead") substituted 'rtl' for 'ltr'.
The paragraph about dynamic movementinitial value for 'min-width' is now '0' rather than UA-dependent.
Corrected "applies to" exception for both 'min-width' and superscripting has been shifted into a non-normative note. C.4.40 Section 9.5 Floats Clarified'max-width'
from "table elements" to "table rows and row groups".
Specified that line boxesnegative values for 'min-width' and 'max-width' are
shortenedillegal.
Added some text to clarify what "Any content in the current line before a floated box is reflowed in the first available line on the other side of the float" means. Clarified floats' position in the stacking order. C.4.41 Section 9.5.1 Positioning the float Clarifiedthat 'auto' height also depends on whether the elements referenced in the float behavior rules are in the same block formatting contextelement has
padding or borders, as the float. C.4.42 Section 9.5.2 Controlling flow nextthese influence margin-collapsing behavior.
Added text to floats Clarified that the effects of 'clear' do not consider floats in other block formatting contexts. C.4.43correctly account for margin collapsing behavior.
Corrected "applies to" exception for both 'min-width' and 'max-width'
from "table elements" to clarify"table columns and column groups".
Specified that the images in this section are not drawn to scalenegative values for 'min-height' and 'max-height'
are illustrations, not reference renderings. C.4.44illegal.
Corrected "applies to" line for 'overflow' from "block-level and replaced elements" to "non-replaced block-level elements, table cells, and inline-block elements".
The example of "containing block" Noted thata DIV element containing block formed by inline elements may wind up witha negativeBLOCKQUOTE containing
block width. C.4.45 Section 10.2 Content width In the definition of <length> values foranother DIV was not rendered correctly. The 'width' property, changed "Specifies a fixed width"first style rule applied
to "Specifies the width ofboth DIVs, so the content area usingsecond DIV box should have been rendered with a
length unit". C.4.46 Section 10.3.3 Block-level, non-replaced elements in normal flow Clarified that setting both left and right margins to 'auto' horizontally centersred border as well. The element within its containing block. C.4.47 Section 10.3.8 Absolutely positioning, replaced elements Clarifiedsecond DIV has now been changed to a CITE,
which part of the text of section 10.3.7 is re-used. C.4.48 Section 10.4 Minimum and maximum widths Clarified that 'min-width' and 'max-width' dodoes not affecthave a red border.
Corrected "rect (<top> <right> <bottom> <left>)" to "rect(<top>, <right>, <bottom>, <left>)".
Corrected initial value of any properties. (They only affect'visibility' to 'visible'.
The example used value.) C.4.49 Section 10.6 Calculating heights and margins Clarified that these rules apply tothe root element just asstyle 'hebrew', which does not exist in CSS
level 2. Changed to 'lower-greek'.
Under the 'list-style' property, the example:
ul > ul { list-style: circle outside } /* Any other element. C.4.50UL child of a UL */
could never match valid HTML markup (since a UL element cannot be a child of another UL element). An LI has been inserted in between.
Second sentence: "In terms of any properties. (They only affectthe used value.) C.4.51 Section 10.8 Line height calculations Removed clarifying note about line height being taller than tallest single inlinebox duemodel, 'background' refers to
vertical alignment. C.4.52 Section 10.8.1 Leading and half-leading Removed "slightly" fromthe note "Valuesbackground of this property have slightly different meaningsthe content and the padding areas" now also
mentions the border area. (See also errata to section
8.1 above.) Thus:
In terms of the
contextbox model, "background" refers to the background oftables."C.4.53Section11.1Overflowthe content, padding andclippingClarifiedborder areas.
Under 'background-image', defined the image tile size used when
absolute positioningthe background image has intrinsic sizes specified in percentages
or no intrinsic size.
Under 'background-repeat',
the sentence "All tiling covers the content and negative margins cause overflow. Added 'text-indent'padding areas [...]"
has been corrected to
"All tiling covers the
listofthingsthatcancauseoverflow.Removedmentionof'clip'sinceitnolongeraffectsmostelements;mentionedthatcontent, padding and border areas [...]".
Under 'background-attachment', the 'overflow' property also specifies whether a scrolling mechanismvalue 'scroll' is provideddefined to
access clipped content. C.4.54 Section 11.1.1 Overflow Clarified that descendant elements whose containing block isscroll with the viewport or an ancestor of"containing block" rather than with the element are not affected by overflow clipping. Removed unnecessary mentions of"document".
Also the 'clip' property fromsentence "Even if the 'hidden' value definition. C.4.55 Section 11.1.2 Clipping Changed "portionimage is fixed [...] background or padding
area of an element's rendered content"the element" has been corrected to
"portionofanelement'sborderbox"sinceclippingalsoaffectsEven if theelement'sbackgroundsandborders.Clarifiedwhatpartsimage is fixed, it is still only visible when it is in the background, padding or border area of theelementareaffectedbyclipping.Clarifiedthatclippedcontentdoesnotcauseoverflow.Clarifiedthatargumentsofclip()canbeseparatedbyspacesorbycommas,butnotacombination.C.4.56element.
In bullet 2, changed "the UA uses the 'font-family' descriptor" to "the UA uses the 'font-family' property".
The :before and :after pseudo-elements Clarified that :before and :after pseudo-elements interact with other boxesstatement "Negative values are not allowed" for 'font-size'
now applies to percentages as if they were real elements just inside their associated element. Noted thatwell as lengths.
Corrected 'text-indent' to apply to table cells (and inline blocks) as well as block-level elements.
Corrected 'text-align' to apply to table cells (and inline blocks) as well as block-level elements.
Changed prose about the interactioneffect of :before and :after with replaced elements'justify' to be less correct.
Corrected the note to say that justification is left undefined for now. C.4.58 Section 12.2also dependent
on the 'content' property Clarified which counters are used for counter() and counters() in case there are multiple countersscript, not just the language, of the same name. C.4.59text.
In the "self-nesting" behaviordefinition of counters, clarified that merely using a counter in a child element does not create a new instance of it: only resetting it does. Clarified that the scope of a counter does not include any elementstable-header-group, changed
"footer" to "header" in the scope of a counter with the same name created by a 'counter-reset'"Print user agents may repeat footer rows on
each page spanned by a later sibling or a later 'counter-reset' on the same element. Removed sentence about scopetable."
Added 'table-header-group' and 'table-footer-group' alongside
mentions of 'counter-increment' without prior 'counter-reset' as that is now defined (differently) under "12.4.1 Nested counters'table-row-group' where missing.
Corrected 'caption' to 'table-caption'.
Added missing rule (#3) for 'table-column' boxes.
Added 'table-caption' and scope." C.4.61 Section 12.4.3 Counters'table-column-group' to list of boxes
requiring a 'table' or 'inline-table' parent in elements with 'display: none' Clarified that pseudo-elements thatrule 4.
Added rules 5 and 6 to generate no'table-row' boxes also do not increment counters. C.4.62where necessary
for children of 'table'/'inline-table' and
'table-row-group'/'table-header-group'/'table-footer-group' boxes.
Specified handling of multiple caption boxes.
Specified that the root background image, although painted over the entire canvas,anonymous outer table box is anchored asa 'block'
box if painted only forthe root element,table is block-level and thatan 'inline-block' box if
the root's backgroundtable is only painted once. Clarified rules for propagation of background settings on HTML's <body> element toinline-level but that the root. Added statement about z-indexanonymous outer table
box cannot accept run-ins.
Correct text that form a stacking context and referredsaid all internal table elements have
padding; change to z-index property for details. Added this note after the first paragraph after 'background-attachment': Notesay that there isof these only one viewport per document. I.e., even if an element has a scrolling mechanism (see 'overflow'), a 'fixed' background doestable cells have
padding.
The following note:
Note. Table cells may be relatively and absolutely positioned, but this is not
movewithit.Definitionof'background-position'recommended: positioning and floating remove a box from the flow, affecting table alignment.
has been rewrittenamended as normative rules rather than just examples. Stated thatfollows:
Note. Table cells may be positioned, but this is not recommended: absolute and fixed positioning, as well as floating, remove a box from the
tilingflow, affecting table size.
The rows and columns only cover the whole table in CSS2.1. C.4.63 Section 15.1 Fonts Introduction Drastically shortened introduction. C.4.64 Section 15.2 Font matching algorithmthe collapsed
borders model, not in the per-property ruleseparated borders model.
The points 2, clarified that 'normal' matches3, 4 and 5 have been corrected to define the non-small-caps variant (if there is one). C.4.65 Section 15.2.2 Font family Removed discussion of font-matching algorithm. (It is alreadyarea
covered in the font-matching algorithm's own section . Clarified that quoted strings that areby rows, columns, row groups and column groups and thus the
same as a keyword value must be treated as font family namespositioning and not aspainting of backgrounds on those elements.
Specify the keyword value (which must be unquoted). C.4.66handling of "missing cells".
In the image, changed "cell-spacing" to "border-spacing".
For the 'ButtonHighlight' value, changed the description from "Dark shadow" to "Highlight color".
Changed "but any descendants which actually create a new stacking context" to "but any positioned descendants and descendants which actually create a new stacking context" (3 times).
This change was made. C.4.67also occurred once in section 9.5 (Floats) and once in
section 15.4 Font styling The textsection 9.9 (Layered
presentation).
This section (formerly part of 15.2.3)has been reverted to its CSS1 format. C.4.68marked non-normative.
This section (formerly part of 15.2.3)has been reverted to its CSS1 format. Clarified that CSS2.1 cannot select font variants besides small-caps. Clarified that when "font-variant: small-caps" results in the substitutionmarked non-normative.
Added a statement about case-sensitivity of full-caps, the behavior is the same asselectors for text-transform. C.4.69 Section 15.6 Font boldnessXML.
The textspecification for the XML
style sheet PI
was written after CSS2 was finalized. The first line of the full XML
example should not have been be <?XML:stylesheet type="text/css"
href="bach.css"?>, but
<?xml-stylesheet type="text/css" href="bach.css"?>
This section (formerly part of 15.2.3)has been revertedmarked non-normative.
Added a note to its CSS1 format. Also, discussion of font-weight from other parts ofclarify that the Fonts chapter has been aggregated under this section. Removed statement that says "User agents must map names to values indeprecated/non-deprecated status
of a wayfeature is distinct from its normative/non-normative status.
Under 'document language' clarified that preserves visual order;CSS only describes the
presentation of a face mappeddocument language, and has no effect on its semantics.
Changed definition of 'replaced element' to a value must"an element whose content
is outside the scope of the CSS formatting model" and added further clarifying
text. This clarifies that e.g., SVG images embedded in an XML document are
also considered replaced elements, not be lighter than faces mappedjust those linked in from an outside
file. Also changed definition of 'rendered content' to lower values."be consistent with this
is otherwise implied by "The only guarantee isclarification.
Added under "Intrinsic dimension" that raster images without
reliable resolution information are assumed to have a face of a given value will be no less dark than the facessize of lighter values." C.4.701 px
unit per image source pixel.
Added definition for 'ignore'.
Added definition for 'HTML user agent'.
Added definition for 'property'.
Moved definitions of font size"immediately before" and "immediately after" forward
so they apply to em squares.the whole Syntax section.
Added a totally irrelevant note about font sizes virtual reality scenes. C.4.71sections 4.1.2.1 and 4.1.2.2 to defined vendor-specific
extensions.
Clarified that text overflowing dueinput that cannot be parsed according to text-indentthe core syntax
is affected byignored according to the 'overflow' property. Added a note about text-indents inheriting behavior and suggesting 'text-indent: 0' on inline-blocks. C.4.72 Section 16.2 Alignment Changed "double justify" to "justify" under "left, right, center, and justify". C.4.73rules for handling parsing errors.
Clarified that input that cannot be tokenized or parsed has no meaning in CSS2.1.
Clarified that when a CRLF pair terminates an example to illustrateescape sequence, the interaction ofpair
is treated as a single white space collapsing and bidi. C.4.76 Section 17.1 Introduction to tables Expanded introduction to include a brief discussion of the two table layout models. Mentioned that the automatic table algorithm is not fully definedcharacter as corrected
in CSS 2.1 butthe tokenization rules.
Replaced "[a-z0-9]" by "[a-zA-Z0-9]" as an extra reminder that some implementations have achieved relatively close interoperability. C.4.77CSS
identifiers are case-insensitive.
Replaced the CSS table model Clarifyterm "{}-block" with "declaration block".
Clarified that all table captions must be rendered if more than one exists. Specifiedproperty:value combinations and @-keywords that replaced elementsdo not
contain an identifier beginning with table display valuesdash or underscore are treated as table elements in table layout. C.4.78reserved by CSS
for future use.
Clarified that when something inside an at-rule is ignored because it is invalid, this does not make the entire at-rule invalid.
Referenced section 17.2.1 Anonymous table objects Moved the first bullet text4.1.7 for parsing invalid bits inside declaration
blocks.
Clarified that '-0' is equivalent to the prose before the list of generation rules as it'0' and is not a general statement of what the rules are supposed to accomplish. C.4.79negative number.
Clarified that "display: table" elements behave as block-level elements and "display: inline-table" elements behave as inline-level elements andnegative length values on properties that do not allow them
cause the other way around.declaration to be ignored.
Reduced unnecessary discussion of what a URI is.
Added note about terminology change ("simple selector") between CSS2 and CSS3.
Clarified that 'table-caption' boxes behave as normal block boxes within the outer anonymous table box.text nodes and comments do not affect whether a
sibling selector matches.
Clarified that percentage 'width'~= and 'height' on the table box is relative to|= by using the anonymous box's containing block, notdefinitions from the anonymous box itself.Selectors
module.
Clarified that the 'position', 'float', 'top', 'right', 'bottom', and 'left'rules about default attribute values on the table boxare used onthe anonymous outer box instead ofsame,
whether the table box anddefault is specified in a DTD or by other means.
Added a note that it depends on the table box itself uses the initial values of those properties. C.4.80document format which
attributes are ID attributes.
Clarified that CSS 2.1 does not define if the following paragraph wasparent
of an element that matches ':active' or ':hover' itself also matches
':active' or ':hover'.
Added after point 6:note that, in CSS1, ':active' only applies to links.
Added a note to show the rows, columns, row groupsdifferences between ':lang(xx)' and
column groups in'[lang=xx]'.
Clarified that digits can also be first letter.
Clarified that computed values are inherited (not specified values)
and that they become the hypothetical grid linesspecified value on whichthe bordersinheritor.
Removed discussion of "default" styles for a document.
Clarify that 'inherit' can be used on properties that are centered. (And thus, in this model, the rows together exactly cover the table, leaving no gaps; ditto fornot normally inherited
and that when set on the columns.) Inroot element, it has the separated borders model,effect of assigning the
edges coincide withproperty's initial value.
Except @charset from the rows and columns, corresponding tostatement that @imports must precede all other rules.
Obfuscated note about positioning of table cells to be more precise about the possibly unintended effects. C.4.81 Section 17.5.1 Table layerssystem settings and transparency At the end of theUA limitations.
Various editorial changes to clarify sort order.
Added a note:
The
followingparagraph:Notethatifspecificity is based only on thetablehas'border-collapse:separate',form of thebackgroundselector. In particular, a selector of theareagivenbyform "[id=p33]" is counted as an attribute selector (a=0, b=1, c=0), even if theattribute is'border-spacing'propertyidalwaysdefined as an "ID" in thebackgroundsource document's DTD.
Clarify that Style rules outside of @media rules apply to the table element. See 17.6.1 C.4.82same
media types that the style sheet itself applies to.
Added a paragraphtext to clarify the interaction of the table width algorithmsthat media types are mutually exclusive,
but a UA can render simultaneously to canvases with the rules indifferent
media types.
Split "aural" media group into "audio" and margins). C.4.83"speech".
The
oneinthissectionevenifitresultsindifferentbehavior.Alsomarkedtherestbackground style of thesectionnon-normativeinaccordancewiththatstatement.C.4.85Section17.5.4HorizontalalignmentinacolumnChanged"Thehorizontalalignmentcontent, padding, and border areas of acell'scontentwithinacellbox is specifiedwithby the'text-align'property"to"Thehorizontalalignment'background' property ofacell'sinlinecontentwithinacellboxcanbespecifiedwiththe'text-align'property."C.4.86Section17.5.5DynamicrowandcolumneffectsClarifiedthatnotaffectinglayoutmeansthat'visibility:collapse'causesthepartgenerating element. Margin backgrounds are always transparent.
Added a sentence to note explainingthat 'border-spacing' can be used as a substitute for the non-standard 'framespacing' attributevertical margins have no effect on frameset elements (which are out-of-scope for CSS2.1). Added clarification about backgrounds: the sentence "This space is filled with the background of the table element" was replaced by: In this space, the row, column, row group, and column group backgrounds are invisible, allowing the table background to show through. C.4.88non-replaced
inline elements.
Changed "absolute maximum" to "maximum of the absolute values" in
sentence after the question,about negative margins collapsing.
Added "and padding-left i and padding-right i referthis clarifying note to the left (resp., right) paddingfirst bullet of cell i." C.4.89 Section 18.2 System Colors Notedthe explanation
of vertical collapsing of margins:
Note. Adjoining boxes may be generated by elements that
systemcolorsaredeprecatedinCSS3.C.4.90Section18.4DynamicoutlinesClarifiednot related as siblings or ancestors.
Emphasized that outlinesfloating elements' margins do not cause overflow. Clarified that outlines are only fully connected "if possible". C.4.91 Section 18.4.1 Outlinescollapse even between a float
and the focus Clarifyits in-flow children.
Emphasized that changing outlines in response to focus shouldabsolutely positioned elements' margins do not cause a document to reflow. C.4.92 Appendix D Default style sheet for HTML 4 Added paragraph clarifying that some presentational markup in HTML can be replaced with CSS, but it requires different markup. C.5 Errata sincecollapse even between
the Candidate Recommendation of July 2007 Errata to CSS 2.1 since CR versionpositioned element and its in-flow children.
Changed description of July 19, 2007. C.5.1 Section 1.4.2.1'none' value [2009-04-15] The notation “&&” may be used in syntax definitions in future CSS specifications. C.5.2 Section 2.3to not imply that all four border
widths are set to zero.
Changed the first part ofsentence "When the sectionviewport is not normative. C.5.3 Section 3.1 Definitions [2007-11-14] Append For raster images without reliable resolution information,smaller than the ..., the user
agent should offer a size of 1 px unit per image source pixel must be assumed.scrolling mechanism" to use "area of the definitioncanvas on
which the document is rendered" instead of intrinsic dimensions. C.5.4"document's initial containing
block".
S* ':' S* value; The DELIM was allowed there soClarified that unofficial properties could start with'display: none' also applies to non-visual media.
Clarified that the definitionmargins of IDENT. [2009-02-02] Change U to u in token UNICODE-RANGE. (It means the same, but seems to avoid confusion.) [2009-02-02] Clarify where comments are allowed: COMMENT tokensfixed positioned boxes do not occur in the grammar (to keep it readable), butcollapse
with any number of these tokens may appear anywhere between outsideother tokens. (Note, however,margins.
Clarified that a comment before or within the @charset rule disables the @charset.) C.5.5 Section 4.1.2.2 Informative Historical Notes [2008-12-09] Other known vendor prefixes are: -xv-, -ah-, prince-, -webkit-,in print media fixed boxes are rendered on every page.
Clarified that negative lengths and -khtml-. C.5.6 Section 4.1.3 Characterspercentages are allowed as values
of 'top', 'right', 'bottom', and case [2007-11-14] In'left'.
Added "For replaced elements, the second bullet, change [a-z0-9] to [a-zA-Z0-9] ; ineffect of this value depends only
on the third bullet, change [0-9a-f] to [0-9a-fA-F] . Althoughintrinsic dimensions of the preceding bullet already says that CSS is case-insensitive,replaced content. See the explicit mention of upper and lower case letters helps avoid mistakes. C.5.7 Section 4.1.3 Characters and case [2008-03-05] CSS is now case-sensitive, except for certain parts: All CSS syntax is case-insensitive withinsections
on the ASCII range (i.e., [a-z]width and [A-Z] are equivalent) , exceptheight of absolutely positioned, replaced elements
for parts that are not underdetails." to the controldefinition of CSS. C.5.8 Section 4.1.3 Characters and case [2008-12-02] The pair “*/” ends a comment, even if preceded by a backslash. Change this sentence'auto' because that's not what
chapter 10 says at all.
Clarified that 'justify' stretches "spaces and words in inline boxes"; previous text simply said that it stretches "inline boxes".
The third bullet: Except within CSS comments, any character (except a hexadecimal digit) can be escaped with a backslash to remove its special meaning. C.5.9 Section 4.1.3 Charactersstatement "When an inline box is split, margins, borders, and
case [2009-04-15] Text added to matchpadding have no visual effect where the grammar: […] any character (except a hexadecimal digit , linefeed, carriage returnsplit occurs." has been
generalized. Margins, borders, and padding have no visual effect
where one or form feed ) can be escaped […] C.5.10 Section 4.1.5 At-rules [2009-04-15]more splits occur.
Clarified that unknown statements are ignored when looking for @import: CSS 2.1 user agents must ignore any '@import' rule that occurs inside a block or after any valid non-ignored statement other thanan @charset or an @import rule. C.5.11 Section 4.1.7 Rule sets, declaration blocks, and selectors [2008-11-26] More precise statementinline box that exceeds the width of what is ignored: Whena user agentline box
and cannot parsebe split therefore overflows the selector (i.e., itline box.
Removed sentence about formatting of margins, borders, and padding for split inline boxes not being fully defined when affected by bidi as that situation is now defined in section 8.6.
Clarified that although relative positioning normally does not
valid CSS 2.1),directly affect layout, it must ignore the selector and the following declaration block (if any) as well. C.5.12 Section 4.2 Rules for handling parsing errors [2009-04-15] Added error recovery rule for unexpected tokens at the top level: Malformed statements. User agents must handle unexpected tokens encountered while parsing a statement by reading untilmay affect layout indirectly through
the endcreation of scrollbars.
Relatively positioned boxes do not always establish new containing
blocks. Changed the statement, while observingsecond paragraph to refer to the rules for matching pairs of (), [], {}, "", and '',section on
containing blocks accordingly.
The paragraph about dynamic movement and correctly handling escapes. For example,superscripting has been
shifted into a malformed statement may contain an unexpected closing brace or at-keyword. E.g., the following linesnon-normative note.
Clarified that line boxes are all ignored: p @here {color: red} /* ruleset with unexpected at-keyword "@here" */ @foo @bar; /* at-rule with unexpected at-keyword "@bar" */ }} {{ - }} /* ruleset with unexpected right brace */ ) [ {} ] p {color: red } /* ruleset with unexpected right parenthesis */ C.5.13 Section 4.2 Rulesshortened to make room for handling parsing errors [2008-11-26] Change “or block” as follows: User agents must ignore an invalid at-keyword together with everything following it, upthe
margin box of the float.
Added some text to and includingclarify what "Any content in the next semicolon (;), or block ({...})current line before
a floated box is reflowed in the next block ({...}), orfirst available line on the endother side of
the block (}) that containsfloat" means.
Clarified floats' position in the invalid at-keyword , whichever comes first. C.5.14 Section 4.3.2 Lengths [2008-08-19] Add recommendation about size of px: […] the user agent should rescale pixel values. It is recommended that the pixel unit refer tostacking order.
Clarified that best approximatesthe reference pixel. C.5.15 Section 4.3.5 Counters [2008-03-05] Insert case-sensitiveelements referenced in Countersthe float behavior
rules are denoted by case-sensitive identifiers . C.5.16 Section 5.8.1 Matching attributes and attribute values [2008-04-07] Clarified ~= and |= by usingin the definitions fromsame block formatting context as the Selectors module. [2008-11-03]float.
Clarified that [foo~=""] (i.e., with an empty value) willthe effects of 'clear' do not match anything. C.5.17 Section 5.8.2 Default attribute valuesconsider floats
in DTDs [2007-11-14] Replace tag selector by type selector . C.5.18 Section 5.11.4 The language pseudo-class: :lang [2009-04-15] The language code is case-insensitive. C.5.19 Section 5.12.3 The :beforeother block formatting contexts.
Added a note to clarify that the :first-letterimages in this section are not
drawn to scale and :first-line pseudo-elementsare combinedillustrations, not reference renderings.
Noted that a containing block formed by inline elements may wind up
with applied to an element havinga negative containing block width.
In the first letter or linedefinition of <length> values for the element including'width' property,
changed "Specifies a fixed width" to "Specifies the inserted text generated content . C.5.20 Section 6.3 The @import rule [2008-08-19] Add “In CSS 2.1” and “Seewidth of the content
area using a length unit".
Clarified that setting both left and right margins to 'auto' horizontally centers the element within its containing block.
Clarified which part of the media listtext of section 10.3.7 is matched. Add at the end: Inre-used.
Clarified that 'min-width' and 'max-width' do not affect the
absencecomputed values of any media types, the import is unconditional. Specifying 'all' for the medium has the same effect. The importproperties. (They only takes effect if the target medium matches the media list. A target medium matches a media list if one of the items in the media list isaffect the target medium or 'all'. Noteused value.)
Clarified that Media Queries [MEDIAQ] extendsthese rules apply to the syntax of media listsroot element just as to
any other element.
Clarified that 'min-width' and 'max-width' do not affect the
definitioncomputed values of matching. Whenany properties. (They only affect the same style sheet is imported or linked to a document in multiple places, user agents must process (or act as though they do) each link as though the link were to a separate style sheet. C.5.22used value.)
Removed clarifying note about line height being taller than tallest single inline box due to vertical alignment.
Removed "slightly" from the meaningnote "Values of a media list: Find all declarations that apply to the element andthis property have
slightly different meanings in question, for the target media type. Declarations apply if the associated selector matchesthe element in questioncontext of tables."
Clarified when absolute positioning and on all links on the path through which the style sheet was reached. C.5.24 Section 7.2.1negative margins cause
overflow.
Added 'text-indent' to the @media rule [2008-12-02]list of things that can cause overflow.
Removed mention of 'clip' since it no longer affects most elements;
mentioned that the rules for parsing unknown statements inside @media blocks were ambiguous. Change'overflow' property also specifies whether a
scrolling mechanism is provided to access clipped content.
Clarified that descendant elements whose containing block is the
first sentence as follows:viewport or an @media rule specifiesancestor of the target media types (separatedelement are not affected by commas) of a setoverflow
clipping.
Removed unnecessary mentions of rules statements (delimited by curly braces). Invalid statements must be ignored per 4.1.7 "Rule sets, declaration blocks, and selectors" and 4.2 "Rules for handling parsing errors." Also make it explicit that CSS level 2 (unlike higher levels) has no nested @-rules. Add atthe end of'clip' property from the section: “ At-rules inside @media are invalid in CSS 2.1. ” C.5.25'hidden'
value definition.
Changed "portion of the topan element's rendered content" to "portion
of an element's border edge is determined by assumingbox" since clipping also affects the element's
backgrounds and borders.
Clarified what parts of the element hasare affected by clipping.
Clarified that clipped content does not cause overflow.
Clarified that arguments of clip() can be separated by spaces or by
commas, but not a non-zero bottom (not: top) border. C.5.26combination.
Clarified that the 'min-height' and 'max-height'descendants of ana 'visibility: hidden' element will
be visible if they have no influence over whether the element's bottom margin is adjoining to its last child's bottom margin. C.5.27'visibility: visible'.
Clarified that :before and :after pseudo-elements interact with
'overflow'other than 'visible', but all block formatting contexts avoid collapsing their margins with their children. Change the third bulletboxes as follows: Vertical margins ofif they were real elements with 'overflow' other than 'visible'just inside their associated
element.
Noted that establish new block formatting contexts (such as floatsthe interaction of :before and elements:after with 'overflow' other than 'visible') do not collapse with their in-flow children. C.5.28 Section 9.2.2 Inline-levelreplaced elements
and inline boxes [2008-12-02] Added missing 'inline-block' in: “Several values ofis left undefined for now.
make an element inline: 'inline', 'inline-table', 'inline-block'Clarified which counters are used for counter() and 'run-in' (partcounters() in
case there are multiple counters of the time; see run-in boxes).” C.5.29 Section 9.2.4same name.
[2008-04-07]Removed note about common typographic practices when quotes in
different languages are mixed.
In the "self-nesting" behavior of counters, clarified that 'display: none' also applies to non-visual media. C.5.30 Section 9.3.2 Box offsets: 'top', 'right', 'bottom', 'left' [2008-08-19] Remove true but confusing note (occurs 4×): Note: For absolutely positioned elements whose containing block is based onmerely
using a block-level element, this property is an offset from the padding edgecounter in a child element does not create a new instance of it:
only resetting it does.
Clarified that element. C.5.31 Section 9.5 Floats [2008-08-19] Positioned descendantsthe scope of a float arecounter does not include any elements
in the stacking contextscope of a counter with the float's parent. Add “positioned elements and” to […] exceptsame name created by a 'counter-reset'
on a later sibling or a later 'counter-reset' on the same element.
Removed sentence about scope of 'counter-increment' without prior
'counter-reset' as that any positioned elementsis now defined (differently) under
"12.4.1 Nested counters and scope."
Clarified that actually create new stacking contexts take part in the float's parent's stacking context. Same change in Section 9.9 Layered presentation : […] exceptpseudo-elements that any positioned elementsgenerate no boxes also do not
increment counters.
Clarified that the root background image, although painted over the entire
canvas, is anchored as if painted only for the root element, and any elementsthat actually create new stacking contexts take part inthe parent stacking context.” C.5.32 Section 9.5 Floats [2008-12-02] Remove “'s”root's
background is only painted once.
Clarified rules for propagation of background settings on HTML's <body> element to the root.
Added statement about z-index of backgrounds for elements that may be misinterpreted: “the float's parent 'sform a
stacking context.” C.5.33 Section 9.5.2 Controlling flow nextcontext and referred to floats: the 'clear'z-index property [2009-02-02] Add an example of negative clearancefor details.
Added this note after the first note. C.5.34 Section 9.6.1 Fixed positioning [2008-11-03] Added: Boxes with fixed positionparagraph after 'background-attachment':
Note that
arelargerthere is only one viewport per document. I.e., even if an element has a scrolling mechanism (see 'overflow'), a 'fixed' background does not move with it.
Definition of 'background-position' has been rewritten as normative rules rather than just examples.
Stated that the page box are clipped. Partstiling and positioning of background images for inline
elements is undefined in CSS2.1.
Drastically shortened introduction.
In the fixed position boxper-property rule 2, clarified that are not visible'normal' matches
the non-small-caps variant (if there is one).
Removed discussion of font-matching algorithm. (It is already
covered in the initial containing block will not print. C.5.35 Section 9.9.1 Specifying the stack level: the 'z-index' property [2008-12-02]font-matching algorithm's
own section.
Clarified that quoted strings that are the list of stacking levels is ambiguous: relatively positioned elements could fall under items 3/4/5 or under item 6. Meant is item 6, so exclude them from 3/4/5same as follows: the backgrounda keyword
value must be treated as font family names and borders of the element formingnot as the stacking context.keyword
value (which must be unquoted).
This section, previously section 15.2.6, has been moved but no other change was made.
The stacking contexts of descendants with negative stack levels. a stacking level containing in-flow non-inline-level non-positioned descendants. a stacking level for non-positioned floats and their contents. a stacking level for in-flow inline-level non-positioned descendants. a stacking leveltext for positioned descendants with 'z-index: auto', and any descendant stacking contexts with 'z-index: 0'. the stacking contexts of descendants with positive stack levels. C.5.36 Section 10.1 Definitionthis section (formerly part of "containing block" [2009-02-02] Rephrase first bullet point to make easier15.2.3) has been
reverted to read:its CSS1 format.
The containing blocktext for this section (formerly part of 15.2.3) has been
reverted to its CSS1 format.
Clarified that CSS2.1 cannot select font variants besides small-caps.
Clarified that when "font-variant: small-caps" results in which the root element lives is a rectangle withthe
dimensionssubstitution of full-caps, the viewport, anchored at the canvas origin for continuous media, andbehavior is the page areasame as for
paged media. This containing block is called the initial containing block. The containing block in which the root element lives is a rectangle calledtext-transform.
The initial containing block.text for continuous media, it has the dimensionsthis section (formerly part of the viewport and is anchored at the canvas origin; it is the page area for paged media. C.5.37 Section 10.3 Calculating widths and margins [2009-04-15] The values15.2.3) has been
reverted to its CSS1 format. Also, discussion of 'left' and 'right' are only determined by section 9.4.3 in the casefont-weight from
other parts of relatively positioned elements: For Points 1-6 and 9-10,the Fonts chapter has been aggregated under this
section.
Removed statement that says "User agents must map names to values
of 'left' and 'right' used for layout in the case of relatively positioned elements are determined by the rules in section 9.4.3. C.5.38 Section 10.3.1 Inline, non-replaced elements [2009-04-15] The only casein which 'left' or 'right' cana way that preserves visual order; a face mapped to a value
must not be 'auto'lighter than faces mapped to lower values." This is
when the elementotherwise implied by "The only guarantee is statically positioned. Inthat case 'left' and 'right are ignored and there is thus no need to determine a used value:a computed valueface of 'auto' for 'left', 'right', 'margin-left' or 'margin-right' becomesa usedgiven
value will be no less dark than the faces of '0'. C.5.39lighter values."
Clarified relationship of 'auto', and the element has an intrinsic width, thenfont size to em squares.
Added a totally irrelevant note about font sizes virtual reality scenes.
Clarified that intrinsic widthtext overflowing due to text-indent is affected
by the used value of 'width'. just before the paragraph beginning Otherwise, if 'width' has'overflow' property.
Added a computed valuenote about text-indents inheriting behavior and suggesting
'text-indent: 0' on inline-blocks.
Changed "double justify" to "justify" under "left, right, center, and justify".
Added an example to illustrate how underlining affects descendant boxes.
Switched language reference from RFC2070 to BCP47.
Added section 16.6.1 as an example
to illustrate the interaction of 'auto', but nonewhite space collapsing and bidi.
Expanded introduction to include a brief discussion of the conditions above are met, […] . C.5.40two
table layout models. Mentioned that the automatic table algorithm
is not fully defined in CSS 2.1 but that some implementations
have achieved relatively close interoperability.
Clarify that all table captions must be rendered if more than one exists.
Specified that replaced elements [2008-03-05] Changewith table display values are
treated as table elements in table layout.
Moved the last paragraphfirst bullet text to the prose before the list of
generation rules as follows: Ifit does, thenis a percentage intrinsic width on that element cannot be resolved andgeneral statement of what the element is assumedrules
are supposed to have no intrinsic width then the resulting layout is undefinedaccomplish.
Clarified that "display: table" elements in normal flow [2008-03-05] Scrollbar widths are no longer included inbehave as block-level elements
and "display: inline-table" elements behave as inline-level elements and
not the containingother way around.
Clarified that 'table-caption' boxes behave as normal block width. Remove scrollbar width from: 'margin-left' + 'border-left-width' + 'padding-left' +boxes
within the outer anonymous table box.
Clarified that percentage 'width' + 'padding-right' + 'border-right-width' + 'margin-right' + scrollbar width (if any) = width of containing blockand from: If 'width''height' on the table box is
relative to the anonymous box's containing block, not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' + scrollbar width (if any) [...]the anonymous
box itself.
Clarified that the 'position', 'float', 'top', 'right', 'bottom',
and remove'left' values on the paragraph:table box are used on the "scrollbar width" value is only relevant ifanonymous outer
box instead of the user agenttable box and that the table box itself uses a scrollbar as its scrolling mechanism. Seethe
definitioninitial values of those properties.
To remove ambiguity about the 'overflow' property. C.5.42 Section 10.3.7 Absolutely positioned, non-replaced elements [2008-03-05] Scrollbar widths are no longer includedposition of extent of internal
table boxes, the following paragraph was added after point 6:
the edges of the rows, columns, row groups and column groups in the
containingblockwidth.Removescrollbarwidthfrom:'left'+'margin-left'+'border-left-width'+'padding-left'+'width'+'padding-right'+'border-right-width'+'margin-right'+'right'+scrollbarwidth(ifany)=widthofcontainingblockandremovetheparagraph:The"scrollbarwidth"valueisonlyrelevantifcollapsing borders model coincide with theuseragentusesascrollbarasitsscrollingmechanism.Seehypothetical grid lines on which thedefinitionborders of the'overflow'property.C.5.43Section 10.3.7Absolutelypositioned,non-replacedelements[2008-03-05]Addcells are centered. (And thus, in this model, thefollowingdefinition.[2008-08-19]Addrows together exactly cover thefollowingnotetothatdefinition.table, leaving no gaps; ditto for thestatic-positioncontainingblockiscolumns.) In thecontainingblockofahypotheticalboxthatwouldhavebeenseparated borders model, thefirstboxedges coincide with the border edges of cells. (And thus, in this model, there may be gaps between theelementifitsspecified'position'propertyhadbeen'static'rows andits'float'hadbeen'none'.(Notethatduecolumns, corresponding to therulesin'border-spacing' property.)
Changed warning note about positioning of table cells to be more precise about the possibly unintended effects.
At the 'direction' propertyend of the element establishingsection added the static-position containing block is [...] C.5.44 Section 10.3.8 Absolutely positioned, replaced elements [2008-03-05] Change bullet 2 as follows: [...]following paragraph:
Note that if the
'direction'propertytable has 'border-collapse: separate', the background of theelementestablishingarea given by thestatic-positioncontainingblock'border-spacing' property is[...]C.5.45Section 10.3.8Absolutelypositioned,replacedelements[2008-03-05]Clarification.ReplaceThissituationissimilartoalways thepreviousone,exceptthatbackground of theelementhasanintrinsicwidth.table element. See 17.6.1
Added a paragraph to clarify the sequenceinteraction of substitutions is now: bythe table width
algorithms with the rules in
this case,section 10.3.7 applies up through10.3
(Calculating widths and includingmargins).
Explicitly mentioned that the constraint equation, butfixed table layout algorithm may be
used with the restalgorithm of section
10.3.710.3.3 when 'table-layout' is replaced by the following rules: C.5.46 Section 10.3.8 Absolutely positioned, replaced elements [2008-04-07]'fixed' but 'width' is 'auto'.
Clarified that margins are not calculated as for inline elements. C.5.47 Section 10.5 Content height: the 'height' property Under “<percentage>,” addUAs can use other algorithms besides the same note as under “<percentage>,”one in
section 10.2 (“Content width: the 'width' property”). C.5.48this section 10.6.2 Inline replaced elements […] [2007-11-14] Add the following paragraph: Otherwise,even if 'height' has a computed valueit results in different behavior.
Also marked the rest of 'auto', andthe element has an intrinsic height, thensection non-normative in accordance
with that intrinsic heightstatement.
Changed "The horizontal alignment of a cell's content within a cell
box is specified with the used value'text-align' property" to "The horizontal
alignment of 'height'. just before the paragraph beginning Otherwise, if 'height' hasa computed value of 'auto', but none ofcell's inline content within a cell box
can be specified with the conditions above are met […] . C.5.49 Section 10.6.4 Absolutely positioned, non-replaced elements [2008-11-26] The static position is determined considering neither float nor clear. Add this: […] and its specified 'float' had been 'none''text-align' property."
Clarified that margins arenot calculated as for inline elements. C.5.51 Section 10.8.1 Leading and half-leading [2007-11-14] Inaffecting layout means that 'visibility: collapse'
causes the Note under 'vertical-align', remove slightly from Valuespart of this property have slightly different meanings inrow- and column-spanning cells that span into
the context of tables. C.5.52 Section 11.1.1 Overflow:collapsed row to be clipped.
Added a note explaining that 'border-spacing' can be used as a
substitute for the containing block width. Replacenon-standard 'framespacing' attribute on
frameset elements (which are out-of-scope for CSS2.1).
Added clarification about backgrounds: the
sentence "This space taken up by the scrollbars affectsis filled with the computationbackground of the dimensionstable
element" was replaced by:
In this space, the
renderingmodel.byAnyspacetakenupbythescrollbarsshouldbetakenoutof(subtractedfromthedimensionsof)thecontainingblockformedbyrow, column, row group, and column group backgrounds are invisible, allowing theelementwithtable background to show through.
In XHTML. Changethe sentence “ HTML UAs must instead apply the 'overflow' property from the BODY element to the viewport, ifafter the value onquestion, added "and
padding-lefti and padding-righti refer
to the HTML element is 'visible'. ” to: Whenleft (resp., right) padding of cell i."
Noted that system colors are deprecated in CSS3.
Clarified that outlines do not cause overflow.
Clarified that outlines are only fully connected "if possible".
Clarify that changing outlines in response to focus should not cause a document to reflow.
Added paragraph clarifying that element has ansome presentational markup in
HTML "BODY" element or an XHTML "body" element as a child, user agents must instead apply the 'overflow' property fromcan be replaced with CSS, but it requires different markup.
Errata to CSS 2.1 since CR version of July 19, 2007.
[2009-04-15] The viewport, ifnotation
“&&” may be used in syntax definitions in future
CSS specifications.
[2008-08-19] The root element is 'visible'. C.5.53 Section 11.1.2 Clipping:first part of the 'clip' property [2008-03-05] Insert (butsection
is not a combination) in User agents must support separation with commas, but may also support separationnormative.
[2007-11-14] Append For raster
images without
to the
commas (but notreliable resolution information, a combination) . C.5.54 Section 12.2size of 1 px
unit per image source pixel must be assumed.'content' property [2009-04-15] (And also in section 12.4:) certain keywords, in particular 'none', 'inherit' and 'initial' (the latter being reserved for future use) cannot be used as names for counters. C.5.55 Section 12.4.2 Counter styles [2008-03-05] Error in example. Replace hebrew by lower-greek: BLOCKQUOTE:after { content: " [" counter(bq, hebrew lower-greek ) "]" } C.5.56 Section 12.5 Lists [2008-12-01] Change “in” to “with respect to” indefinition of intrinsic dimensions.
[2007-09-27] Remove DELIM?
from
the listgrammar rule
declaration :DELIM?property S* ':' S* value;
The DELIM was allowed there so that unofficial properties describe basic visual formatting of lists: they allow style sheets to specifycould
start with a dash (-), but the marker type (image, glyph, or number), anddash was already allowed because of the
marker positiondefinition of IDENT.
[2009-02-02] Change U to
u in with respecttoken UNICODE-RANGE. (It means the same, but seems to
avoid confusion.)
[2009-02-02] Clarify where comments are allowed:
COMMENT tokens do not occur in the
principalbox(outsidegrammar (to keep it readable), but any number of these tokens may appear anywherebetweenoutside other tokens. (Note, however, that a comment before or withinitbeforecontent).becausethemarkeris,astherestof@charset rule disables thesentenceitselfmakesclear,notnecessarily@charset.)
[2008-12-09] Other known vendor prefixes are: -xv-, -ah-, prince-, -webkit-, and -khtml-.
[2007-11-14] In the principal box. C.5.57 Section 12.5.1 Lists:second bullet, change
to [a-z0-9][a-zA-Z0-9]
; in the
'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2008-04-07]third bullet, change
to
[0-9a-f][0-9a-fA-F]
.
Although the size of list style markers without an intrinsic size is now defined. C.5.58 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2008-12-01] CSS 2.1 does not specify the position of the list item marker, but does require it to be on the left or right of the content. Also, the marker is not affected by 'overflow', but may influence the height of the principal box. Add to the definition of 'outside': … but does requirepreceding bullet already says that for list items whose 'direction' propertyCSS is
'ltr' the marker box be oncase-insensitive, the left sideexplicit mention of the contentupper and for elements whose 'direction' propertylower case letters
helps avoid mistakes.
[2008-03-05] CSS is 'rtl' the marker box be on the right side of the content. 'overflow' on the element does not clip the marker box. The marker boxnow case-sensitive,
except for certain parts:
All CSS syntax is
fixedwithrespecttocase-insensitive within theprincipalblockbox'sborderASCII range (i.e., [a-z] anddoes[A-Z] are equivalent), except for parts that are notscrollwiththeprincipalblockbox'scontent.Thesizeorcontentsofthemarkerboxmayaffecttheheightoftheprincipalblockboxand/orunder theheightcontrol ofitsfirstlinebox,CSS.
[2008-12-02] The creation ofpair “*/” ends
a new line box. Note:comment, even if preceded by a backslash. Change this interaction may be more precisely definedsentence in
a future level of CSS. C.5.59 Section 12.5.1 Lists:the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2009-04-015] Meaning of 'none' for 'list-style' was only defined by an example. C.5.60 Section 13.2 Page boxes:third bullet:
Except within CSS comments, any character (except a hexadecimal digit) can be escaped with a backslash to remove its special meaning.
[2009-04-15] Text added to match the @page rule [2008-08-19] Add rulesgrammar:
[…] any character (except a hexadecimal digit , linefeed, carriage return or form feed) can be escaped […]
[2009-04-15] Clarified that unknown
statements are ignored when looking for drawing canvas to: The page area. The page area includes the boxes laid out on@import:
CSS 2.1 user agents must ignore any '@import' rule that
page.Theedgesoccurs inside a block or after anyvalidnon-ignored statement other than an @charset or an @import rule.
[2008-11-26] More precise statement of what is ignored:
When a user agent cannot parse the
firstpageareaestablishtherectanglethatselector (i.e., it is not valid CSS 2.1), it must ignore theinitialcontainingselector and the following declaration block (if any) as well.
[2009-04-15] Added error recovery rule for unexpected tokens at the top level:
Malformed statements. User agents must handle unexpected tokens encountered while parsing a statement by reading until the end of the
document.statement, while observing thecanvasbackgroundispaintedwithinrules for matching pairs of (), [], {}, "", andcoversthepagearea.'', and correctly handling escapes. For example, a malformed statement may contain an unexpected closing brace or at-keyword. E.g., themarginfollowing lines are all ignored:p @here {color: red} /* ruleset with unexpected at-keyword "@here" */ @foo @bar; /* at-rule with unexpected at-keyword "@bar" */ }} {{ - }} /* ruleset with unexpected right brace */ ) [ {} ] p {color: red } /* ruleset with unexpected right parenthesis */
[2008-11-26] Change “or block” as follows:
User agents must ignore an invalid at-keyword together with everything following it, up to and including the next semicolon (;),
or block ({...})the next block ({...}), or the end of the block (}) that contains the invalid at-keyword, whichever comes first.
[2008-08-19] Add recommendation about size of px:
[…] the user agent should rescale pixel values. It is recommended that the pixel unit refer to the whole number of device pixels that best approximates the reference pixel.
[2008-03-05] Insert case-sensitive
in Counters are denoted by case-sensitive
identifiers
.
[2008-04-07] Clarified ~= and |= by using the definitions from the Selectors module.
[2008-11-03] Clarified that [foo~=""] (i.e., with an empty value) will not match anything.
[2007-11-14] Replace
by tag
selectortype selector
.
[2009-04-15] The language code is case-insensitive.
[2008-11-03] Clarified text:
When the :first-letter and :first-line pseudo-elements are
combined withapplied to an element having content generated using :before and :after, they apply to the first letter or line of the element including theinserted textgenerated content.
[2008-08-19] Add “In CSS 2.1” and “See the section on parsing for when user agents must ignore @import rules” to
In CSS 2.1, any @import rules must precede all other rules (except the @charset rule, if present). See the section on parsing for when user agents must ignore @import rules.
[2008-11-26] Define what it means to import a style sheet twice and how the media list is matched. Add at the end:
In the absence of any media types, the import is unconditional. Specifying 'all' for the medium has the same effect. The import only takes effect if the target medium matches the media list.
A target medium matches a media list if one of the items in the media list is the target medium or 'all'.
Note that Media Queries [MEDIAQ] extends the syntax of media lists and the definition of matching.
When the same style sheet is imported or linked to a document in multiple places, user agents must process (or act as though they do) each link as though the link were to a separate style sheet.
[2007-11-22] Spelling error:
prece
.
ndence
[2008-11-26] Define the meaning of a media list:
Find all declarations that apply to the element and property in question, for the target media type. Declarations apply if the associated selector matches the element in question and the target medium matches the media list on all @media rules containing the declaration and on all links on the path through which the style sheet was reached.
[2008-12-02] The rules for parsing unknown statements inside @media blocks were ambiguous. Change the first sentence as follows:
An @media rule specifies the target media types (separated by commas) of a set of
rulesstatements (delimited by curly braces). Invalid statements must be ignored per 4.1.7 "Rule sets, declaration blocks, and selectors" and 4.2 "Rules for handling parsing errors."
Also make it explicit that CSS level 2 (unlike higher levels) has no nested @-rules. Add at the end of the section: “At-rules inside @media are invalid in CSS 2.1.”
[2008-08-18] In bullet 6, sub-bullet 2, the position of the top border edge is determined by assuming the element has a non-zero bottom (not: top) border.
[2009-02-02] Rephrased the rule for adjoining margins so that the 'min-height' and 'max-height' of an element have no influence over whether the element's bottom margin is adjoining to its last child's bottom margin.
[2008-12-02] Not only elements with 'overflow' other than 'visible', but all block formatting contexts avoid collapsing their margins with their children. Change the third bullet as follows:
- Vertical margins of elements
with 'overflow' other than 'visible'that establish new block formatting contexts (such as floats and elements with 'overflow' other than 'visible') do not collapse with their in-flow children.
[2008-12-02] Added missing 'inline-block' in: “Several values of the 'display' property make an element inline: 'inline', 'inline-table', 'inline-block' and 'run-in' (part of the time; see run-in boxes).”
[2008-04-07] Clarified that 'display: none' also applies to non-visual media.
[2008-08-19] Remove true but confusing note (occurs 4×):
Note: For absolutely positioned elements whose containing block is based on a block-level element, this property is an offset from the padding edge of that element.
[2008-08-19] Positioned descendants of a float are in the stacking context of the float's parent. Add “positioned elements and” to
[…] except that any positioned elements and elements that actually create new stacking contexts take part in the float's parent's stacking context.
Same change in Section 9.9 Layered presentation:
[…] except that any positioned elements and any elements that actually create new stacking contexts take part in the parent stacking context.”
[2008-12-02] Remove “'s” that
may be misinterpreted: “the float's parent's stacking
context.”
[2009-02-02] Add an example of negative clearance after the first note.
[2008-11-03] Added:
Boxes with fixed position that are larger than the page box are clipped. Parts of the fixed position box that are not visible in the initial containing block will not print.
[2008-12-02] The list of stacking levels is ambiguous: relatively positioned elements could fall under items 3/4/5 or under item 6. Meant is item 6, so exclude them from 3/4/5 as follows:
- the background and borders of the element forming the stacking context.
- the stacking contexts of descendants with negative stack levels.
- a stacking level containing in-flow non-inline-level non-positioned descendants.
- a stacking level for non-positioned floats and their contents.
- a stacking level for in-flow inline-level non-positioned descendants.
- a stacking level for positioned descendants with 'z-index: auto', and any descendant stacking contexts with 'z-index: 0'.
- the stacking contexts of descendants with positive stack levels.
[2009-02-02] Rephrase first bullet point to make easier to read:
The containing block in which the root element lives is a rectangle with the dimensions of the viewport, anchored at the canvas origin for continuous media, and the page area for paged media. This containing block is called the initial containing block.
The containing block in which the root element lives is a rectangle called the initial containing block. For continuous media, it has the dimensions of the viewport and is anchored at the canvas origin; it is the page area for paged media.
[2009-04-15] The values of 'left' and 'right' are only determined by section 9.4.3 in the case of relatively positioned elements:
For Points 1-6 and 9-10, the values of 'left' and 'right'
used for layoutin the case of relatively positioned elements are determined by the rules in section 9.4.3.
[2009-04-15] The only case in which 'left' or 'right' can be 'auto' is when the element is statically positioned. In that case 'left' and 'right are ignored and there is thus no need to determine a used value:
A computed value of 'auto' for
'left', 'right','margin-left' or 'margin-right' becomes a used value of '0'.
[2007-11-14] Add the following paragraph:
Otherwise, if 'width' has a computed value of 'auto', and the element has an intrinsic width, then that intrinsic width is the used value of 'width'.
just before the paragraph beginning Otherwise, if 'width' has a
computed value of 'auto', but none of the conditions above are met,
[…]
.
[2008-03-05] Change the last paragraph as follows:
If it does,
then a percentage intrinsic width on that element cannot be resolved and the element is assumed to have no intrinsic widththen the resulting layout is undefined in CSS2.1.
[2008-03-05] Scrollbar widths are no longer included in the containing block width. Remove scrollbar width from:
'margin-left' + 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' + 'margin-right'
+ scrollbar width (if any)= width of containing block
and from:
If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width'
+ scrollbar width (if any)[...]
and remove the paragraph:
The "scrollbar width" value is only relevant if the user agent uses a scrollbar as its scrolling mechanism. See the definition of the 'overflow' property.
[2008-03-05] Scrollbar widths are no longer included in the containing block width. Remove scrollbar width from:
'left' + 'margin-left' + 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' + 'margin-right' + 'right'
+ scrollbar width (if any)= width of containing block
and remove the paragraph:
The "scrollbar width" value is only relevant if the user agent uses a scrollbar as its scrolling mechanism. See the definition of the 'overflow' property.
[2008-03-05] Add the following definition.
[2008-08-19] Add the following note to that definition.
The static-position containing block is the containing block of a hypothetical box that would have been the first box of the element if its specified 'position' property had been 'static' and its 'float' had been 'none'. (Note that due to the rules in section 9.7 this hypothetical calculation might require also assuming a different computed value for 'display'.)
And change which 'direction' property is used as follows (two occurrences):
[...] if the 'direction' property of the element establishing the static-position containing block is [...]
[2008-03-05] Change bullet 2 as follows:
[...] if the 'direction' property of the element establishing the static-position containing block is [...]
[2008-03-05] Clarification. Replace
This situation is similar to the previous one, except that the element has an intrinsic width. The sequence of substitutions is now:
by
In this case, section 10.3.7 applies up through and including the constraint equation, but the rest of section 10.3.7 is replaced by the following rules:
[2008-04-07] Clarified that margins are not calculated as for inline elements.
Under “<percentage>,” add the same note as under “<percentage>,” in section 10.2 (“Content width: the 'width' property”).
[2007-11-14] Add the following paragraph:
Otherwise, if 'height' has a computed value of 'auto', and the element has an intrinsic height, then that intrinsic height is the used value of 'height'.
just before the paragraph beginning Otherwise, if 'height' has a
computed value of 'auto', but none of the conditions above are
met […]
.
[2008-11-26] The static position is determined considering neither float nor clear. Add this:
[…] and its specified 'float' had been 'none' and 'clear' had been 'none'.
[2008-04-07] Clarified that margins are not calculated as for inline elements.
[2007-11-14] In the Note under
'vertical-align', remove slightly
from Values of
this property have
slightly different meanings in the
context of tables.
[2008-03-05] Scrollbar widths are no longer included in the containing block width. Replace
The space taken up by the scrollbars affects the computation of the dimensions in the rendering model.
by
Any space taken up by the scrollbars should be taken out of (subtracted from the dimensions of) the containing block formed by the element with the scrollbars.
[2008-11-03] 'Overflow' on BODY is special
not only in HTML but also in XHTML. Change the sentence
“HTML UAs must instead apply the 'overflow' property from
the BODY element to the viewport, if the value on the HTML element is
'visible'.” to:
When the root element is an HTML "HTML" element or an XHTML "html" element, and that element has an HTML "BODY" element or an XHTML "body" element as a child, user agents must instead apply the 'overflow' property from the first such child element to the viewport, if the value on the root element is 'visible'.
[2008-03-05] Insert (but not a
combination)
in User agents must support separation with
commas, but may also support separation without commas (but not a
combination)
.
[2009-04-15] (And also in section 12.4:) certain keywords, in particular 'none', 'inherit' and 'initial' (the latter being reserved for future use) cannot be used as names for counters.
[2008-03-05] Error in example. Replace hebrew by lower-greek:
BLOCKQUOTE:after { content: " [" counter(bq, hebrew lower-greek) "]" }
[2008-12-01] Change “in” to “with respect to” in
The list properties describe basic visual formatting of lists: they allow style sheets to specify the marker type (image, glyph, or number), and the marker position
inwith respect to the principal box (outside it or within it before content).
because the marker is, as the rest of the sentence itself makes clear, not necessarily in the principal box.
[2008-04-07] The size of list style markers without an intrinsic size is now defined.
[2008-12-01] CSS 2.1 does not specify the position of the list item marker, but does require it to be on the left or right of the content. Also, the marker is not affected by 'overflow', but may influence the height of the principal box. Add to the definition of 'outside':
… but does require that for list items whose 'direction' property is 'ltr' the marker box be on the left side of the content and for elements whose 'direction' property is 'rtl' the marker box be on the right side of the content. 'overflow' on the element does not clip the marker box. The marker box is fixed with respect to the principal block box's border and does not scroll with the principal block box's content. The size or contents of the marker box may affect the height of the principal block box and/or the height of its first line box, and in some cases may cause the creation of a new line box. Note: This interaction may be more precisely defined in a future level of CSS.
[2009-04-015] Meaning of 'none' for 'list-style' was only defined by an example.
[2008-08-19] Add rules for drawing canvas to:
- The page area. The page area includes the boxes laid out on that page. The edges of the first page area establish the rectangle that is the initial containing block of the document. The canvas background is painted within and covers the page area.
- The margin area, which
surroundssurrounds the page area. The page margin area is transparent.
[2009-02-02]
Remove sections 13.2.1.1 and 13.2.1.2. (The described situations cannot occur in CSS 2.1, because CSS 2.1 does not have a 'size' property.)
[2008-11-03] Clarified what locations are inconvenient for printing:
When formatting content in the page model, some content may end up outside the current page box. For example, an element whose 'white-space' property has the value 'pre' may generate a box that is wider than the page box. As another example, when boxes are positioned absolutely or relatively, they may end up in “inconvenient” locations. For example, images may be placed on the edge of the page box or 100,000 meters below the page box.
[2008-04-30] The 'page-break-inside' property no longer inherits.
[2008-12-01] UAs may apply 'page-break-before', 'page-break-after' and 'page-break-inside' to other elements than block-level ones.
[2009-02-02] “Paragraph” is not
a defined term. Change of a paragraph to in a block
element (twice).
[2009-04-15] 'Widows' and 'orphans' only accept positive values.
[2008-04-30] The 'page-break-inside' property of all ancestors is checked for page-breaking restrictions, not just that of the breakpoint's parent.
[2009-02-02] Remove possible confusion:
Rule D: In addition, breaking at (2) is allowed only if the 'page-break-inside' property of the element and all its ancestors is 'auto'.
[2009-02-02] Top margins do not disappear at a page break that is forced by a 'page-break-after' or 'page-break-before'. Correct the first bullet to:
When an unforced page break occurs here, the used values of the relevant 'margin-top' and 'margin-bottom' properties are set to '0'. When a forced page break occurs here, the used value of the relevant 'margin-bottom' property is set to '0'; the relevant 'margin-top' used value may either be set to '0' or retained.
And add the following note:
Note: It is expected that CSS3 will specify that the relevant 'margin-top' applies (i.e., is not set to '0') after a forced page break.
[2009-02-02] Remove the advice to user agents to avoid breaking inside elements with borders, inside tables or inside floating elements; add the advice to avoid breaking inside replaced elements.
[2008-11-03] The 'background' property is special on BODY not only in HTML but also in XHTML.
[2009-04-15] The whole 'background' property is used for the canvas, not just the color and the image:
For documents whose root element is an HTML "HTML" element or an XHTML "html" element that has computed values of 'transparent' for 'background-color' and 'none' for 'background-image', user agents must instead use the computed value of
thosethe background properties from that element's first HTML "BODY" element or XHTML "body" element child […]
[2008-04-07] The size of background images without an intrinsic size is now defined.
[2008-11-26] Remove incorrect text:
- 'bolder' selects the next weight that is assigned to a font that is darker than the inherited one.
If there is no such weight, it simply results in the next darker numerical value (and the font remains unchanged), unless the inherited value was '900' in which case the resulting weight is also '900'.- 'lighter' is similar, but works in the opposite direction: it selects the next lighter keyword with a different font from the inherited one,
unless there is no such font, in which case it selects the next lighter numerical value (and keeps the font unchanged).
and:
The computed value of "font-weight" is either:
one of the legal number values, orone of the legal number values combined with one or more of the relative values (bolder or lighter). This type of computed values is necessary to use when the font in question does not have all weight variations that are needed.
And instead add this note:
Note: A set of nested elements that mix 'bolder' and 'lighter' will give unpredictable results depending on the UA, OS, and font availability. This behavior will be more precisely defined in CSS3.
[2008-08-19] Remove rules about generated text from:
The following examples show what whitespace behavior is expected from the PRE and P elements, the “nowrap” attribute in HTML,
and in generated content.pre { white-space: pre } p { white-space: normal } td[nowrap] { white-space: nowrap }:before,:after { white-space: pre-line }
[2009-02-02] Collapsing of white space does not remove any line breaking opportunities. Add the following clarification:
Then, the entire block is rendered. Inlines are laid out, taking bidi reordering into account, and wrapping as specified by the 'white-space' property. When wrapping, line breaking opportunities are determined based on the text prior to the white space collapsing steps above.
[2007-11-14] Spelling error:
boxes
.
s
[2008-10-13] Added new rule after bullet 4:
5. If a child T of a 'table', 'inline-table', 'table-row-group', 'table-header-group', 'table-footer-group', or 'table-row' box is an anonymous inline box that contains only white space, then it is treated as if it has 'display: none'.
[2009-02-02] The anonymous block containing the table and its caption establishes a block formatting context:
The anonymous box is a 'block' box if the table is block-level, and an 'inline-block' box if the table is inline-level
except that this block is never considered as a block for 'run-in' interaction, and thatThe anonymous box establishes a block formatting context. The table box (not the anonymous box) is used when doing baseline vertical alignment for an 'inline-table'.
The diagram now shows the caption's margins inside the anonymous box.
[2008-04-07] Clarification:
The horizontal alignment of a cell's inline content within a cell box
iscan be specifiedwith the 'text-align' propertyby the value of the 'text-align' property on the cell.
[2008-04-07] The size of cursors without an intrinsic size is now defined.
[2007-11-14] Spelling error: change
to ?likÇelik
(2×).
[2008-08-19] Replace
br:before { content: "\A" }
:before, :after { white-space: pre-line }
with
br:before { content: "\A"; white-space: pre-line }
[2008-08-19] Add tr to:
td, th, tr { vertical-align: inherit }
[2007-11-14] Replace but any descendants
which actually create a new stacking context
by but any
positioned descendants and descendants which actually
create a new stacking context
.
[2007-09-27] Change the last S
in
the grammar rule for combinator
to
S+
:
combinator : PLUS S* | GREATER S* | S+
and remove the rule
{s}+\/\*[^*]*\*+([^/*][^*]*\*+)*\/ {unput(' '); /*replace by space*/}
in the tokenizer. The resulting language is the same, but the grammar is easier to read and relies less on specific notations of Flex.
[2007-09-27] Changes to remove ambiguity with respect to the S token and avoid nullable non-terminals.
[2007-09-27] Change the tokenizer rule
@{C}{H}{A}{R}{S}{E}{T}{return CHARSET_SYM;}
to
"@charset " {return CHARSET_SYM;}
The @charset must be in lowercase and must have a space after it (as defined in section 4.4 CSS style sheet representation).
[2008-03-05] Change the tokenizer rules
"url("{w}{string}{w}")" {return URI;}"url("{w}{url}{w}")" {return URI;}
to
{U}{R}{L}"("{w}{string}{w}")" {return URI;}
{U}{R}{L}"("{w}{url}{w}")" {return URI;}
[2008-04-07] The definition of the macro
“O” is wrong. The letters O
and o can be written with hexadecimal escapes as
“\4f” and “\6f”
respectively (not as “\51” and
“\71”). The macro should therefore be
O o|\\0{0,4}(4f|6f)(\r\n|[ \t\r\n\f])?|\\o
“The two occurrences of "\377"…”: There is in fact only one occurrence.
Add a TITLE attribute to all links and which is equal to the lemma.
These are the errata for CSS level 2 revision 1, CR version of 23 April 2009. These corrections have the status of a draft.
[2009-08-06] Clarified the rules for ignoring invalid at-keywords:
Invalid at-keywords. User agents must ignore an invalid at-keyword together with everything following it, up to the end of the block that contains the invalid at-keyword, or up to and including the next semicolon (;), or up to and including the next block ({...}),
or the end of the block (}) that contains the invalid at-keyword,whichever comes first.
[2009-08-06] Page breaks are also allowed when there is a gap after the last content of a block. Added the following to the first list:
3. Between the content edge of a block box and the outer edges of its child content (margin edges of block-level children or line box edges for inline-level children) if there is a (non-zero) gap between them.
[2009-08-31] The list of keywords in “(e.g., 'initial', 'inherit', 'default', 'serif', 'sans-serif', 'monospace', 'fantasy', and 'cursive')” isn't an example, but is in fact the complete and normative list.
[2009-08-31] Spelling errors in font names. The correct names are “Excelsior Cyrillic Upright” and “ER Bukinist.”
[2009-08-31] The two notes “Note: implementation experience has demonstrated…” and “Note 2. In CSS1, the suggested scaling factor… say essentially the same thing. They are replaced by a single note:
Note 2. In CSS1, the suggested scaling factor between adjacent indexes was 1.5, which user experience proved to be too large. In CSS2, the suggested scaling factor for a computer screen between adjacent indexes was 1.2, which still created issues for the small sizes. Implementation experience has demonstrated that a fixed ratio between adjacent absolute-size keywords is problematic, and this specification does not recommend such a fixed ratio.
[2009-05-20] UAs may render extra columns if there are unexpected columns in later rows of a 'fixed' table layout. In that case, the width of the columns and of the table is undefined.
[2009-08-06] Replaced
“Percentage heights on table cells, table rows, and table
row groups compute to 'auto' by
CSS 2.1 does not define how the height of table cells and table rows is calculated when their height is specified using percentage values. CSS 2.1 does not define the meaning of 'height' on row groups.
[2009-08-06] Removed ambiguities from the grammar. (The ambiguities only affected spaces and were harmless.)
These are the errata for CSS level 2 revision 1, CR version of 8 September 2009. These corrections have the status of a draft.
[2010-08-06] (Also in various other sections throughout the specification.) Distinguished all cases where the word value referred to a whole property value from where it referred to only part of such a value (such as a component in a comma-separated list). The former is now property value, the latter component value.
[2010-04-19] Add a clarification to the definition of replaced element:
The content of replaced elements is not considered in the CSS rendering model.
(Previously, the definition only said that the content was “outside the scope of CSS.”)
[2010-04-19] The definition of
“identifier” in 4.1.3 (2nd bullet) and in the grammar were
contradictory w.r.t. whether no-break space (U+00A0) was allowed in
identifiers or not. Change the text in 4.1.3 to allow no-break space:
“characters U+00A1 U+00A0 and
higher.”
Also, change the macro “nonascii” in the token
definition from “[^\0-\177]” to
[^\0-\237]”. (When CSS was first written, Unicode
didn't have code points U+0080 to U+009F, i.e., \200-\237 in octal.)
[2010-09-29] The tokenizer has been modified so that it can be implemented as a state machine without back-up (e.g., with Lex). This changes the meaning of an input of the form “url(…(…)…)”, i.e., input that starts like a URI token but then contains a parenthesis (which is not allowed in a URI token). Previously, such input was re-parsed to yield a FUNCTION token followed by other things; now it yields a BAD_URI token. Given that CSS has never used a FUNCTION token of the form “url(” this should not affect any existing CSS style sheets.
A non-normative section has been added to appendix G with an explanation of how to make a tokenizer without back-up.
[2010-09-29] The definition of the URI token was ambiguous: it allowed a backslash to be either parsed on its own or as part of an escape. A backslash in a URI token must always be interpreted as part of an escape.
[2010-09-29] Error handling for illegal tokens (braces, at-keywords, and SGML comment tokens) inside parenthesized expressions was not well defined. Change the production for “any” as follows
any : [ IDENT | NUMBER | PERCENTAGE | DIMENSION | STRING
| DELIM | URI | HASH | UNICODE-RANGE | INCLUDES
| DASHMATCH | ':' | FUNCTION S* [any|unsused]* ')'
| '(' S* [any|unused]* ')' | '[' S* [any|unused]* ']'
] S*;
unused : block | ATKEYWORD S* | ';' S* | CDO S* | CDC S*;
and add the following explanation:
The "unused" production is not used in CSS and will not be used by any future extension. It is included here only to help with error handling. (See 4.2 "Rules for handling parsing errors.")
[2010-04-19] Add “-tc-” to the list of existing vendor prefixes.
[2010-08-06] The handling of a backslash before a newline or at the end of a file is no longer undefined: it is parsed as a DELIM.
[2010-08-06] Make text and formal grammar the same:
In CSS, identifiers […]; they cannot start with a digit, two hyphens, or a hyphen followed by a digit.
[2010-05-12] Remove “2.1” from
Every CSS
2.1property has its own syntactic and semantic restrictions
[2010-07-07] Clarify that the fifth bullet only applies to at-rules. (At-keywords in other constructs are already handled in the preceding bullets.)
Invalid at-keywordsAt-rules with unknown at-keywords. User agents must ignore…
[2010-04-19] Make explicit that 'ex', when used in the 'font-size' property, refers to the parent element's 'ex' (just as 'em' refers to the parent's 'em' in that case.)
[2010-10-28] A UA must now either display absolute lengths (cm, in, pt, etc.) at their real size or make px align with device pixel boundaries near the 0.0213 degrees viewing angle, but not both. In either case, 3px must equal 4pt.
(Until now, authors could use absolute lengths for physical sizes and px for aligning to device pixels, but couldn't know the number of pt in a px, except in combination with Media Queries. Authors can no longer choose between absolute or device-related units, but can use px and pt interchangeably. This should only affect relatively low-resolution devices: above 300 dots per inch, the maximum error is about 16%.)
[2010-05-12] Commas do not have to be escaped in <uri> tokens:
Some characters appearing in an unquoted URI, such as parentheses,
commas,white space characters, single quotes (') and double quotes ("), must be escaped
[2010-04-21] Describe in English what was only expressed through the grammar:
Note. Since URIs may contain characters that would otherwise be used as delimiters in CSS, the entire URI value must be treated as a single unit by the tokenizer and normal tokenization behavior does not apply within a URI value. Therefore comments are not allowed within a URI value.
[2010-09-29] Clarify what is meant by “is not required”:
More precisely, a UA may, but is not required to, read an "external subset" of the DTD but is required to look for default attribute values in the document's "internal subset." (See [XML10] for definitions of these subsets.) Depending on the UA, a default attribute value defined in the external subset of the DTD might or might not appear in the document tree.
A UA that recognizes an XML namespace [XMLNAMESPACES] may, but is not required to, use its knowledge of that namespace to treat default attribute values as if they were present in the document. (E.g., an XHTML UA is not required to use its built-in knowledge of the XHTML DTD.)
and:
the first rule
willmight not match elements whose "notation" attribute is set by default, i.e., not set explicitly. To catch all cases, the attribute selector for the default value must be dropped:
[2010-08-06] The argument of ':lang()' is only case-insensitive for characters in ASCII.
[2010-08-06] Clarify that pseudo-elements behave like elements for the aspects not explicitly mentioned:
Pseudo-elements behave just like real elements in CSS with the exceptions described below and elsewhere.
[2010-08-24] More consistent use of “block” and “block-level.” Change:
The :first-line pseudo-element can only be attached to a
block-level element, inline-block, table-caption or a table-cellblock container element.
[2010-08-24] More consistent use of “block” and “block-level.” Change:
The :first-letter pseudo-element applies to
block, list-item, table-cell, table-caption and inline-block elementsblock container elements.
[2010-08-06] Add a note that, because it follows the document tree, inheritance is not intercepted by anonymous boxes
[2010-10-05] Give other languages than HTML (such as SVG) the possibility to define certain attributes as “presentational attributes”:
For other languages, all document language-based styling
should be handled in the user agent style sheetmust be translated to the corresponding CSS and either enter the cascade at the user agent level or, as with HTML presentational hints, be treated as author level rules with a specificity of zero placed at the start of the author style sheet.
[2010-09-08] Clarify what is ignored. Change:
@media and @import rules with unknown media types (that are nonetheless valid identifiers) are treated as if the unknown media types are not present. If an @media/@import rule contains a malformed media type (not an identifier) then the statement is invalid.
Note: Media Queries supercedes this error handling.
[2010-05-12] Simplify/clarify text:
An element that has
hadclearanceapplied to itnever collapses
and:
When an element's own margins collapse, and that element has
hadclearanceapplied to it
[2010-08-24] More consistent use of “block box” vs “block-level element.” Include table captions in the set of block-level elements. See also changes to 9.2.1 and to 9.2.1.1.
Two or more adjoining vertical margins of block-level boxes in the normal flow collapse.
and
The top margin of an in-flow
block-level elementblock box is adjoining to its first in-flow block-level child's top margin
and
The bottom margin of an in-flow
block-level elementblock box with a 'height' of 'auto'
[2010-08-24] Define the term “block-level element” more precisely. Also define auxiliary terms “block container box” and “block box”:
More consistent use of block box vs block-level element in section 9.2.1.1. See also changes to section 8.3.1 and 9.4.
[2010-05-12] The example has invalid HTML mark-up. Change it to use P and SPAN elements instead of BODY and P.
[2010-08-06] Also clarify that “block box” only refers to boxes in the same flow.
[2010-09-29] Percentage values that refer to dimensions of parent boxes ignore any intervening anonymous boxes. Add this paragraph:
Anonymous block boxes are ignored when resolving percentage values that would refer to it: the closest non-anonymous ancestor box is used instead. For example, if the child of the anonymous block box inside the DIV above needs to know the height of its containing block to resolve a percentage height, then it will use the height of the containing block formed by the DIV, not of the anonymous block box.
[2010-09-29] Clarify the wording:
When an inline box contains an in-flow block box […] When such an inline box is affected by relative positioning, the relative positioning also affects the block-level box contained in the block box.
[2010-10-13] Clarify that an inline box that is broken around a block-level box is always broken into two pieces, even if one or both are empty:
When an inline box contains an in-flow block-level box, the inline box (and its inline ancestors within the same line box) are broken around the block-level box, dividing the inline box into two pieces, even if either side is empty..
[2010-08-24] Better define the term “inline-level element/box” and define the auxiliary terms “inline box” and “atomic inline-level box.”
[2010-04-19] Make the definition of 'run-in' more precise:
A run-in box behaves as follows:
If the run-in box contains a block box, the run-in box becomes a block box.If a sibling block box (that does not float and is not absolutely positioned) follows the run-in box, the run-in box becomes the first inline box of the block box. A run-in cannot run in to a block that already starts with a run-in or that itself is a run-in.Otherwise, the run-in box becomes a block box.A run-in element (or pseudo-element) A behaves as follows:
- If A has any children that inhibit run-in behavior (see below), then A is rendered as if it had 'display: block'.
- Let B be the first of A's following siblings that is neither floating nor absolutely positioned nor has 'display: none'. If B exists and has a specified value for 'display' of 'block' or 'list-item' and is not replaced, then A is rendered as an 'inline' element at the start of B's principal box. Note: A is rendered before B's ':before' pseudo-element, if any. See 12.1.
- Otherwise, A is rendered as if it had 'display: block'.
In the above, "siblings" and "children" include both normal elements and :before/:after pseudo-elements.
An element or pseudo-element C inhibits run-in behavior if one of the following is true. (Note that the definition is recursive.)
- C is not floating and not absolutely positioned and the computed value of its 'display' is one of 'block', 'list-item', 'table' or 'run-in'.
- C has a computed value for 'display' of 'inline' and it has one or more children that inhibit run-in behavior. (Where "children" includes both normal elements and :before/:after pseudo-elements.)
It remains undefined how 'run-in' and ':first-line' interact:
It is undefined in CSS 2.1 if a run-in inherits from a ':first-line' pseudo-element.
[2010-08-06] Use the same terminology as in chapter 12:
- list-item
- This value causes an element (e.g., LI in HTML) to generate a principal block box and a
list-item inlinemarker box.
[2010-08-24] More consistent use of “inline-level.”
- inline-block
- This value causes an element to generate
a block box, which itself is flowed as a single inline box, similar to a replaced elementan inline-level block container. The inside of an inline-block is formatted as a block box, and the element itself is formatted as aninline replaced elementan atomic inline-level box.
[2010-08-24] More consistent use of “inline-level” and “block-level.”
- Normal flow. In CSS 2.1, normal flow includes block formatting of block-level boxes, inline formatting of inline-level boxes, relative positioning of block-level
orand inline-level boxes, andpositioningformatting of run-in boxes.
[2010-08-24] More consistent use of “inline-level” and “block-level.”
Boxes in the normal flow belong to a formatting context, which may be block or inline, but not both simultaneously. Block-level boxes participate in a block formatting context. Inline-level boxes participate in an inline formatting context.
In 9.4.1:
Floats, absolutely positioned elements,
inline-blocks, table-cells, table-captions, and elements with 'overflow' other than 'visible' (except when that value has been propagated to the viewport) establish new block formatting contextsblock containers (such as inline-blocks, table-cells, and table-captions) that are not block boxes, and block boxes with 'overflow' other than 'visible'.In a block formatting context, boxes are laid out one after the other, vertically, beginning at the top of a containing block. The vertical distance between two sibling boxes is determined by the 'margin' properties. Vertical margins between adjacent block-level boxes in a block formatting context collapse.
In 9.4.2:
[…] When several inline-level boxes cannot fit horizontally within a single line box, they are distributed among two or more vertically-stacked line boxes.
When the total width of the inline-level boxes on a line […]is less than the width of the line box containing them, their horizontal distribution within the line box is determined by the 'text-align' property. If that property has the value 'justify', the user agent may stretch spaces and words in inline boxes (
except forbut not inline-table and inline-block boxes) as well.
[2010-07-19] If 'top', 'right', 'bottom' or 'left' is specified as 'auto', the used value rather than the computed value is set to the negative of the opposite side. For all four, change:
Computed value: for 'position:relative', see section Relative Positioning.For 'position:static', 'auto'. Otherwise: if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'.
And in section 9.4.3:
[…] Since boxes are not split or stretched as a result of 'left' or 'right', the
computedused values are always: left = -right.If both 'left' and 'right' are 'auto' (their initial values), the
computedused values are '0' (i.e., the boxes stay in their original position).If 'left' is 'auto', its
computedused value is minus the value of 'right' (i.e., the boxes move to the left by the value of 'right').If 'right' is specified as 'auto', its
computedused value is minus the value of 'left'.[…] Since boxes are not split or stretched as a result of 'top' or 'bottom', the
computedused values are always: top = -bottom. If both are 'auto', theircomputedused values are both '0'. If one of them is 'auto', it becomes the negative of the other. If neither is 'auto', 'bottom' is ignored (i.e., thecomputedused value of 'bottom' will be minus the value of 'top').
[2010-08-24] More consistent use of “inline-level” and “block-level.”
[…] In other words, if inline-level boxes are placed on the line before a left float is encountered that fits in the remaining line box space, the left float is placed on that line, aligned with the top of the line box, and then the inline-level boxes already on the line are moved accordingly to the right of the float (the right being the other side of the left float) and vice versa for rtl and right floats.
In 9.5.2:
Values have the following meanings when applied to non-floating block-level boxes:
[2010-10-25] Define exactly what it means for a line box to be next to a float:
[…] However, line boxes created next to the float are shortened to make room for the margin box of the float.
A line box is next to a float when there exists a vertical position that satisfies all of these four conditions: (a) at or below the top of the line box, (b) at or above the bottom of the line box, (c) below the top margin edge of the float, and (d) above the bottom margin edge of the float.
Note: this means that floats with zero height or negative height do not move line boxes.
[2010-05-12] Clarify that 'clear' only introduces clearance above an element if necessary; and that clearance may have zero height.
[2010-10-13] Added an example of calculating clearance from two collapsing margins M1 and M2 and the height H of a float.
[2010-10-13] Clarify the language:
Computing the clearance of an element on which 'clear' is set is done by first determining the hypothetical position of the element's top border edge within its parent block.
This position is determined after the top margin of the element has been collapsed with previous adjacent margins (including the top margin of the parent block).This position where the actual top border edge would have been if the element had a non-zero top border and its 'clear' property had been 'none'.If this hypothetical position of the element's top border edge is not past the relevant floats, then clearance
must beis introduced, and margins collapse according to the rules in 8.3.1.Then the amount of clearance is set to the greater of:
- The amount necessary to place the border edge of the block even with the bottom outer edge of the lowest float that is to be cleared.
The amount necessary to make the sum of the following equal to the distance to which these margins collapsed when the hypothetical position was calculated:
the margins collapsing above the clearancethe clearance itselfif the block's own margins collapse together: the block's top marginif the block's own margins do not collapse together: the margins collapsing below the clearanceThe amount necessary to place the top border edge of the block at its hypothetical position.
[2010-10-13] Correction: The hypothetical position is determined by assuming the box has a non-zero bottom border (see section 8.3.1):
This position is where the actual top border edge would have been if the element had a non-zero
topbottom border and its 'clear' property had been 'none'.
[2010-04-19] 'Fixed' backgrounds in paged media are positioned relative to the page box (and thus repeat on every page, just like 'fixed' elements). The position of fixed backgrounds in paged media was previously undefined.
[2010-07-07] Some ambiguities in the description of stacking contexts are fixed and the description is clearly marked as non-normative. (Appendix E holds the normative description.)
[2010-08-24] More consistent use of “inline-level” and “block-level.”
User agents that support bidirectional text must apply the Unicode bidirectional algorithm to every sequence of inline-level boxes uninterrupted by a forced line break or block boundary. This sequence forms the "paragraph" unit in the bidirectional algorithm. The paragraph embedding level is set according to the value of the 'direction' property of the containing block rather than by the heuristic given in steps P2 and P3 of the Unicode algorithm.
[…]
For the 'direction' property to affect reordering in inline
-levelelements, the 'unicode-bidi' property's value must be 'embed' or 'override'.[…]
- normal
- The element does not open an additional level of embedding with respect to the bidirectional algorithm. For inline
-levelelements, implicit reordering works across element boundaries.- embed
- If the element is inline
-level, this value opens an additional level of embedding with respect to the bidirectional algorithm. The direction of this embedding level is given by the 'direction' property. Inside the element, reordering is done implicitly. This corresponds to adding a LRE (U+202A; for 'direction: ltr') or RLE (U+202B; for 'direction: rtl') at the start of the element and a PDF (U+202C) at the end of the element.- bidi-override
- For inline
-levelelements this creates an override. Forblock-level, table-cell, table-caption, or inline-blockblock container elements this creates an override for inline-level descendants not within another block-level, table-cell, table-caption, or inline-block element. This means that inside the element, reordering is strictly in sequence according to the 'direction' property; the implicit part of the bidirectional algorithm is ignored. This corresponds to adding a LRO (U+202D; for 'direction: ltr') or RLO (U+202E; for 'direction: rtl') at the start of the element or at the start of each anonymous child block box, if any, and a PDF (U+202C) at the end of the element.The final order of characters in each
block-level elementblock container is […]
[2010-10-05] Add a reference to bidi class B in Unicode TR 9 to clarify what a “forced break” is in the context of the Unicode bidi algorithm:
[…] inline-level boxes uninterrupted by a forced
line(bidi class B) break or block boundary
[2010-10-25] clarify “non-textual entities”:
In this process,
non-textual entities such as imagesreplaced elements with 'display: inline' (and replaced elements with 'display: run-in', when they generate inline-level boxes) are treated as neutral characters, [&hellip]
[2010-08-24] More consistent use of “inline-level” and “block-level.”
- […]
- For other elements, if the element's position is 'relative' or 'static', the containing block is formed by the content edge of the nearest
block-level, table cell or inline-blockblock container ancestor box.- […]
- […]
- In the case that the ancestor is
inline-levelan inline box, the containing block depends on the 'direction' property of the ancestor:
[2010-05-12] The computed value of 'width' doesn't depend on whether the property applies or not:
Computed value: the percentage or 'auto' as specified or the absolute length;
'auto' if the property does not apply
[2010-08-24] More consistent use of “inline-level” and “block-level.”
This property specifies the content width of boxes
generated by block-level and replaced elements.This property does not apply to non-replaced inline
-levelelements.
[2010-10-05] Remove unclear and redundant sentence:
The width of a replaced element's box is intrinsic and may be scaled by the user agent if the value of this property is different than 'auto'.
[2010-05-12] The computed value of 'height' doesn't depend on whether the property applies or not:
Computed value: the percentage or 'auto' (see prose under <percentage>) or the absolute length;
'auto' if the property does not apply
[2010-08-24] More consistent use of “inline-level” and “block-level.”
This property specifies the content height of boxes
generated by block-level, inline-block and replaced elements.This property does not apply to non-replaced inline
-levelelements. See the section on computing heights and margins for non-replaced inline elements for the rules used instead.
[2010-08-06] Clarify “bottom” and “preceding”:
In certain cases (see
the preceding sectionse.g., sections 10.6.4 and 10.6.6), the height of an element that establishes a block formatting context is computed as follows:[…]
In addition, if the element has any floating descendants whose bottom margin edge is below the
bottomthe element's bottom content edge, then the height is increased to include those edges. Only floats that are children of the element itself or of descendants in the normal flow are taken into account, e.g., floats inside absolutely positioned descendants or other floats are not.
[2010-10-26] The effect of 'min-height' and 'max-height' on table cells is still undefined in CSS:
In CSS 2.1, the effect of 'min-height' and 'max-height' on table cells, table rows, and row groups is undefined.
[2010-06-02] Clarifications to the calculation of the line boxes and the minimum line height ("strut"). Item 2 in the bulleted list is expanded and items 3 and 4 are merged, as follows:
- The height of each inline box in the line box is calculated (see "Calculating heights and margins" and the 'line-height' property).
- The inline boxes are aligned vertically according to their 'vertical-align' property. In case they are aligned 'top' or 'bottom', they must be aligned so as to minimize the line box height. If such boxes are tall enough, there are multiple solutions and CSS 2.1 does not define the position of the line box's baseline (i.e., the position of the strut, see below).
- The line box height is the distance between the uppermost box top and the lowermost box bottom. (This includes the strut, as explained under 'line-height' below.)
If the resulting height is smaller than the minimal height of line boxes for this block, as specified by the 'line-height' property, the height is increased to be that minimal height.
Furthermore, in 10.8.1, after the definition of “strut,” clarify that the font determines the initial baseline:
The height and depth of the font above and below the baseline are assumed to be metrics that are contained in the font. (For more details, see CSS level 3.)
[2010-08-24] More consistent use of “inline-level” and “block-level.”
As described in the section on inline formatting contexts, user agents flow inline-level boxes into a vertical stack of line boxes. The height of a line box is determined as follows:
- The height of each inline-level box in the line box is calculated (see "Calculating heights and margins" and the 'line-height' property).
- The inline-level boxes are aligned vertically according to their 'vertical-align' property.
In 10.8.1:
On a
block-level, table-cell, table-caption or inline-blockblock container element whose content is composed of inline-level elements, 'line-height' specifies the minimal height of line boxes within the element. […]On an inline
-levelelement, 'line-height' specifies the height that is used in the calculation of the line box height […]
After the definition of 'vertical-align':
The following values only have meaning with respect to a parent inline
-levelelement, or to the strut of a parentblock-level, table-cell, table-caption or inline-blockblock container element.
[2010-07-19] Clarify text:
On a block-level, table-cell, table-caption or inline-block element whose content is composed of inline-level elements, 'line-height' specifies the minimal height of line boxes within the element. The minimum height consists of a minimum height above the
block'sbaseline and a minimum depth below it, exactly as if each line box starts with a zero-width inline box with theblock'selement's font and line height properties.(what TEX calls a "strut").We call that imaginary box a "strut." (The name is inspired by TeX.).
[2010-08-20] Remove text that talks about the “content area” of an inline box and about “center vertically” and instead make it more explicit how leading is added to a glyph: leading is added above and below a hypothetical box around each glyph that represents the (normal or ideal) height of a line of text in that font, as given in the font metrics.
Add a note referring to 10.6.1 (which defines that the content area is undefined) and explaining that the exact position of backgrounds and borders relative to the line box is undefined.
Also add a note about how to find the relevant metrics in OpenType and TrueType fonts.
[2010-08-20] Clarify some imprecise terms:
When an element contains text that is rendered in more than one font, user agents may determine the 'normal' 'line-height' value according to the largest font size.
Generally, when there is only one value of 'line-height' for all inline boxes in a
paragraphblock-level box (and notall imagesreplaced elements, inline-block elements, etc.), the above will ensure that baselines of successive lines are exactly 'line-height' apart. This is important when columns of text in different fonts have to be aligned, for example in a table.
[2010-10-25] Clarify which ancestors are meant:
- A descendant box is positioned absolutely, partly outside the box. Such boxes are not always clipped by the overflow property on their ancestors; specifically, they are not clipped by the overflow of any ancestor between themselves and their containing block
[2010-08-06] The phrase “containing
block” in the example doesn't refer to the technical term “containing block” but simply to the containing
box. Change “containing block” to
“containing div.”
[2010-08-24] More consistent use of “inline-level” and “block-level.”
This property specifies whether content of a
block-levelblock container element is clipped when it overflows the element's box.
[2010-10-25] Add missing inline-table:
Applies to: non-replaced block-level elements, table cells, inline-table, and inline-block elements
[2010-10-25] The computed value of 'auto' is 'auto' also when 'auto' is specified inside 'rect()':
Computed value: For rectangle values, a rectangle consisting of four computed lengths; otherwise, as specified'auto' if specified as 'auto', otherwise a rectangle with four values, each of which is 'auto' if specified as 'auto' and the computed length otherwise
And:
<top>, <right>, <bottom>, and <left> may either have a <length> value or 'auto'. Negative lengths are permitted. The value 'auto' means that a given edge of the clipping region will be the same as the edge of the element's generated border box (i.e., 'auto' means the same as '0' for <top> and <left> (in left-to-right text, <right> in right-to-left text), the same as the
computedused value of the height plus the sum of vertical padding and border widths for <bottom>, and the same as thecomputedused value of the width plus the sum of the horizontal padding and border widths for <right> (in left-to-right text, <left> in right-to-left text), such that four 'auto' values result in the clipping region being the same as the element's border box).
[2010-10-05] Improve wording: the marker box of a list item isn't “optional,” it is sometimes absent. Change:
CSS 2.1 offers basic visual formatting of lists. An element with 'display: list-item' generates a principal box for the element's content
and an optional marker boxand, depending on the values of 'list-style-type' and 'list-style-image', possibly also a marker box as a visual indication that the element is a list item.
[2010-07-14] Because of persistent incompatibilites between implementations, the constraints on the position of 'outside' markers are relaxed in the presence of floats. This will be fixed in a future specification.
[2010-08-06] The 'armenian' list-style-type refers to uppercase Armenian numbering.
[2010-08-06] Define the order of 'inside' marker boxes and ':before' pseudo-elements:
- inside
- The marker box is placed as the first inline box in the principal block box,
after which the element's content flowsbefore the element's content and before any :before pseudo-elements.
[2010-08-06] CSS 2.1 does not specify the precise location of an 'outside' marker box, including its z-order. Append:
CSS 2.1 does not specify the precise location of the marker box or its position in the painting order
[2010-11-25] Because of historical ambiguity, CSS level 2 does not yet require the marker to be visible when 'list-style-position' is 'outside' and 'overflow' is other than 'visible'. Insert in the definition of 'outside':
In CSS 2.1, a UA may hide the marker if the element's 'overflow' is other than 'visible'. (This is expected to change in the future.)
[2010-07-07] The @page rule can contain not just declarations but also other @-rules. (There aren't any such nested @-rules defined in level 2, but there are in level 3.)
An @page rule consists of the keyword "@page", followed by an optional page selector, followed by a block
of declarationscontaining declarations and at-rules.Note: CSS level 2 has no at-rules that may appear inside @page, but such at-rules are expected to be defined in level 3.
And add just above section 13.2.1:
The rules for handling malformed declarations, malformed statements, and invalid at-rules inside @page are as defined in section 4.2, with the following addition: when the UA expects the start of a declaration or at-rule (i.e., an IDENT token or an ATKEYWORD token) but finds an unexpected token instead, that token is considered to be the first token of a malformed declaration. I.e., the rule for malformed declarations, rather than malformed statements is used to determine which tokens to ignore in that case.
[2010-10-25] Whether the first page of a
document is :left or :right depends on the page area.major writing
direction. Give an example of how:
All pages are automatically classified by user agents into either the :left or :right pseudo-class. Whether the first page
marginareaof a document istransparent.C.5.61Section 13.2.1.1Rendering:left or :right depends on the major writing direction of the root element. For example, the first pageboxesthatdonotfitof atargetsheet[2009-02-02]Removesections13.2.1.1document with a left-to-right major writing direction would be a :right page, and the first page of a document with a right-to-left major writing direction would be a :left page. To explicitly force a document to begin printing on a left or right page, authors can insert a page break before the first generated box.
And 13.2.1.2. (The described situations cannot occurin CSS 2.1, because CSS 2.1 does not have13.3.1:
Whether the first page of a'size'property.)C.5.62Section 13.2.3Contentoutsidedocument is :left or :right depends on the major writing direction of the document.
[2010-08-24] More consistent use of “inline-level” and “block-level.” Change for both 'orphans' and 'widows':
Applies to: block-levelblock container elements
And change:
The 'orphans' property specifies the minimum number of lines in a block
elementcontainer that must be left at the bottom of a page. The 'widows' property specifies the minimum number of lines in a blockelementcontainer that must be left at the top of a page. Examples of how they are used to control pagebox[2008-11-03]Clarifiedwhatlocationsbreaks areinconvenientforprinting:Whenformattinggiven below.
[2010-08-24] More consistent use of “inline-level” and “block-level.” Change:
- In the vertical margin between block-level boxes. […]
- Between line boxes inside a block container box.
- Between the content
inedge of a block container box and thepagemodel,someouter edges of its child contentmayendupoutside[…]
has the value 'pre' may generate a box that is wider than[2010-07-19] The page box.specification was
ambiguous as another example, when boxes are positioned absolutely or relatively , they may end upto whether parentheses, brackets and braces in “inconvenient” locations. For example, images mayfont names
must always be placed onescaped, or only when needed to conform to the
edgesyntax for declarations. Because of that, and because of the page boxmany bugs
in implementations, all font names must now either be quoted,
or 100,000 meters below the page box. C.5.63 Section 13.3.1 Page break properties: 'page-break-before', 'page-break-after', 'page-break-inside' [2008-04-30] The 'page-break-inside' property no longer inherits. C.5.64 Section 13.3.1 Page break properties: 'page-break-before', 'page-break-after', 'page-break-inside' [2008-12-01] UAs may apply 'page-break-before', 'page-break-after' and 'page-break-inside'be escaped so as to other elements than block-level ones. C.5.65 Section 13.3.2 Breaks inside elements: 'orphans', 'widows' [2009-02-02] “Paragraph” isconsist of only identifiers.
[2010-08-26] Make it clearer that CSS does
not a defined term. Changetry to define what fonts are serif or sans-serif:
15.3.1.1 serif
Glyphs of
aparagraphserif fonts, as the term is used in CSS, tend to have finishing strokes, flared or tapering ends, or have actual serifed endings (including slab serifs). [&hellip]15.3.1.2 sans-serif
Glyphs in
ablockelement(twice).C.5.66Section 13.3.2Breaksinsideelements:'orphans','widows'[2009-04-15]'Widows'sans-serif fonts, as the term is used in CSS, tend to have stroke endings that are plain –without anywith little or no flaring, cross stroke, or other ornamentation. […]
[2010-04-19] The meaning of the keywords
'bolder' and 'orphans''lighter' no longer depends on both the inherited weight
and the actually used font, but only accept positive values. C.5.67 Section 13.3.3 Allowed page breaks [2008-04-30]on the 'page-break-inside'inherited weight.
of all ancestors is checked[2010-10-13] Clarify the algorithm for
page-breaking restrictions, not just thatmapping CSS font weight values to the actual weights of a font and
make it normative:
The
breakpoint'sparent.C.5.68Section 13.3.3Allowedpagebreaks[2009-02-02]Removepossibleconfusion:RuleD:Inaddition,breakingat(2)association of other weights within a family to the numerical weight values isallowedintended onlyifto preserve the'page-break-inside'propertyordering of darkness within that family. However, theelementandallitsancestorsfollowing heuristics tell how the assignment is'auto'.C.5.69Section 13.3.3Allowedpagebreaks[2009-02-02]Topmarginsdonotdisappearatdone in typical cases:
- If the font family already uses a
pagebreakthatnumerical scale with nine values (like e.g., OpenType does), the font weights should be mapped directly.- If there is
forcedbyboth a'page-break-after'face labeled Medium and one labeled Book, Regular, Roman or'page-break-before'.CorrectNormal, then thefirstbulletto:Whenanunforcedpagebreakoccurshere,Medium is normally assigned to theusedvaluesof'500'.- The
relevant'margin-top'and'margin-bottom'propertiesaresetfont labeled "Bold" will often correspond to'0'.Whenaforcedpagebreakoccurshere,theusedweight valueof'700'.Once the
relevant'margin-bottom'propertyissetto'0';font family's weights are mapped onto therelevant'margin-top'usedvaluemayeitherbesetto'0'orretained.AndaddCSS scale, missing weights are selected as follows:
If there are fewer then 9 weights in thefollowingnote:Note:Itfamily, the default algorithm for filling the "holes" isexpectedthatCSS3as follows. If '500' is unassigned, it willspecifythatbe assigned therelevant'margin-top'applies(i.e.,isnotsetto'0')afteraforcedpagebreak.C.5.70Section 13.3.5"Best"pagebreaks[2009-02-02]Removesame font as '400'. If any of theadvicetouseragentsvalues '600', '700', '800' or '900' remains unassigned, they are assigned toavoidbreakinginsideelementswithborders,insidetablesthe same face as the next darker assigned keyword, if any, orinsidefloatingelements;addtheadvicenext lighter one otherwise. If any of '300', '200' or '100' remains unassigned, it is assigned toavoidbreakinginsidereplacedelements.C.5.71Section 14.2thebackground[2008-11-03]next lighter assigned keyword, if any, or the'background'propertynext darker otherwise.- If the desired weight is
specialonBODYnotonlyinHTML butalsoless than 400, weights below the desired weight are checked inXHTML.C.5.72Section 14.2descending order followed by weights above thebackground[2009-04-15]desired weight in ascending order until a match is found.- If the
whole'background'propertydesired weight isusedforgreater than 500, weights above desired weight are checked in ascending order followed by weights below thecanvas,notjustdesired weight in descending order until a match is found.- If the
colordesired weight is 400, 500 is checked first and then theimage:rule fordocumentswhoserootelementdesired weights less than 400 isanHTML"HTML"elementoranXHTML"html"elementthathascomputedvaluesof'transparent'for'background-color'used.- If the desired weight is 500, 400 is checked first and
'none'for'background-image',useragentsmustinsteadusethen thecomputedvalueofthoserule for desired weights less than 400 is used.
[2010-08-06] Changed “Percentages:
refer to parent element's first HTML "BODY" element or XHTML "body" element child […] C.5.73 Section 14.2.1 Background properties: 'background-color', 'background-image', 'background-repeat', 'background-attachment', 'background-position',font size” to
“Percentages: refer to inherited font size” so
that it uses the same terminology as Section 4.3.3.
[2010-08-24] More consistent use of
“inline-level” and 'background' [2008-04-07]“block-level.” Change:
Applies to: block-level elements, table cells and inline blocksblock containers[…]
This property specifies the
sizeindentation ofbackgroundimageswithoutanintrinsicsizeisnowdefined.C.5.74Section 15.6Fontboldness:the'font-weight'property[2008-11-26]Removeincorrecttext:'bolder'selectsthenextweightthatisassignedtofirst line of text in afontblock container.
[2010-10-25] Clarify that is darker thanthe inherited one. If there“first
line” of the “first box,” etc., is no such weight, it simply results inthe next darker numerical value (andsame as the
font remains unchanged), unless“first formatted line” of chapter 5:
'Text-indent' only affects a line if it is the
inheritedvaluewas'900'inwhichcasefirst formatted line of an element. For example, theresultingweightfirst line of an anonymous block box isalso'900'.'lighter'only affected if it issimilar,butworksintheoppositedirection:itselectsfirst child of its parent element.
[2010-07-19] The inherited one, unless therevalue 'pre-line' of
'white-space' does not inhibit justification. (Only lines
that end with an explicit newline aren't justified, as is no such font, in which case it selectsthe next lighter numericalcase for
any value (and keeps the font unchanged) . and:of 'white-space'.) But, 'pre-wrap' does inhibit
justification. Replace
If the computed value of"font-weight"text-align iseither:oneof'justify' while thelegalnumbervalues,computed value of white-space is 'pre' orone'pre-line', the actual value of text-align is set to thelegalnumbervaluescombinedinitial value.
with
oneIf an element has a computed value for 'white-space' of 'pre' ormore'pre-wrap', then neither the glyphs of that element's text content nor its white space may be altered for the purpose of justification.
[2010-08-24] More consistent use of “inline-level” and “block-level.” Change:
Applies to: block-level elements, table cells and inline blocksblock containersThis
typeproperty describes how inline-level content ofcomputedvaluesa block container isnecessarytousewhenthefontaligned.
And:
[…] In
questiondoesnothaveallweightvariationsthatareneeded.Andinsteadaddthisnote:Note:Asetofnestedelementsthatmix'bolder'and'lighter'willgiveunpredictableresultsdependingontheUA,OS,case of 'left', 'right' andfontavailability.'center', thisbehaviorwillbemorepreciselydefinedinCSS3.C.5.75Section 16.6Whitespace:the'white-space'property[2008-08-19]Removerulesaboutgeneratedtextfrom:specifies how thefollowingexamplesshowwhatwhitespacebehaviorisexpectedfrominline-level boxes within each line box align with respect to thePREline box's left andPelements,right sides; alignment is not with respect to the“nowrap”attributeinHTML,andviewport. Ingeneratedcontent.pre{white-space:pre}p{white-space:normal}td[nowrap]{white-space:nowrap}:before,:after{white-space:pre-line}C.5.76Section 16.6.1the'white-space'processingmodel[2009-02-02]Collapsingcase ofwhitespacedoesnotremoveanylinebreakingopportunities.Add'justify', this property specifies that thefollowingclarification:Then,inline-level boxes are to be made flush with both sides of theentireblockisrendered.Inlinesarelaidout,takingbidireorderingintoaccount,andwrappingasspecifiedcontainer if possible, by expanding or contracting the'white-space'property.Whenwrapping,linebreakingopportunitiesaredeterminedbasedoncontents of inline boxes, else aligned as for thetextpriortoinitial value.
[2010-08-24] Clarify that 'text-decoration' does not propagate to inline-table and inline-block elements. Change:
This property describes decorations that are added
newruleafterbullet 4:5.IfachildTto the text ofa'table','inline-table','table-row-group','table-header-group','table-footer-group',or'table-row'boxisan element using the element's color. When specified onan inline element, it affects all the boxes generated by that element; for all other elements, the decorations are propagated to an anonymous inline box thator propagated to an inline element, itcontainsonlywhitespace,thenwraps all the in-flow inline children of the element, and to any block-level in-flow descendants. It istreatedasifnot, however, further propagated to floating and absolutely positioned descendants, nor to the contents of 'inline-table' and 'inline-block' descendants.has'display:none'.C.5.79Section 17.4Tablesinaffects all thevisualboxes generated by that element, and is further propagated to any in-flow block-level boxes that split the inline (see section 9.2.1.1). For block containers that establish an inline formattingmodel[2009-02-02]context, the decorations are propagated to an anonymous inline element that wraps all the in-flow inline-level children of the blockcontainingcontainer. For all other elements it is propagated to any in-flow children. Note that text decorations are not propagated to floating and absolutely positioned descendants, nor to thetablecontents of atomic inline-level descendants such as inline blocks anditscaptionestablishesinline tables.
and:
If an element contains no text, user agents must refrain from rendering these text decorations on the element. For example, images will not be underlined.User agents must not render these text decorations on content that is not text. For example, images and inline blocks must not be underlined.
[2010-10-05] CSS 2.1 does not specify
if a block formatting context:text decoration that is specified on a transparent element
('visibility: hidden') is itself transparent, or only transparent
where the anonymous boxtext is a 'block' boxtransparent. Add this note:
Note. If an element E has both 'visibility: hidden' and 'text-decoration: underline', the
tableunderline isblock-level,andan'inline-block'boxinvisible (although any decoration of E's parent is visible.) However, CSS 2.1 does not specify if thetableunderline isinline-levelexceptthatvisible or invisible in E's children:<span style="visibility: hidden; text-decoration: underline"> <span style="visibility: visible"> underlined or not? </span> </span>This
blockisneverconsideredasablockfor'run-in'interaction,expected to be specified in level 3 of CSS.
[2010-04-19] Word spacing does not affect fixed-width spaces. Change:
Word spacing affects each space (U+0020)
,and non-breaking space (U+00A0)and ideographic space (U+3000), left inacolumn[2008-04-07]Clarification:thehorizontalalignmentofacell'sinlinecontentwithinacellboxiscanbespecifiedwithtext after the'text-align'propertybywhite space processing rules have been applied. Thevalueeffect of the'text-align'property on other word-separator characters is undefined. However general punctuation, characters with zero advance width (such as thecell.C.5.81Section 18.1Cursors:zero with space U+200B) and fixed-width spaces (such as U+3000 and U+2000 through U+200A) are not affected.
[2008-04-07][2010-10-25] If the size of cursors without an intrinsic size is now defined. C.5.82 Section B.2 Informative references [2007-11-14] Spelling error: change ? lik to Ç elik (2×). C.5.83 Appendix D. Default style sheet for HTML 4 [2008-08-19] Replace br:before { content: "\A" } :before, :after { white-space: pre-line }document language
specifies how newlines are represented, those newlines must be passed
to the CSS UA as line feed (LF) characters. If the document language
does not define how newlines are expressed (e.g., if text is inserted
with br:before { content: "\A"; white-space: pre-line } C.5.84 Appendix D. Default style sheet for HTML 4 [2008-08-19] Add tr to: td, th , tr { vertical-align: inherit } C.5.85 Section E.2 Painting order [2007-11-14] Replace but any descendants which actually createthe 'content' property), the CSS UA must treat CR, and CRLF as if
they were LF:
Newlines in the source can be represented by a
newstackingcontextcarriage return (U+000D), a linefeed (U+000A) or both (U+000D U+000A) or bybutanypositioneddescendantssome other mechanism that identifies the beginning anddescendantswhichactuallycreateanewstackingcontext.C.5.86AppendixG.Grammarend of document segments, such as the SGML RECORD-START and RECORD-END tokens. The CSS2.1[2007-09-27]Change'white-space' processing model assumes all newlines have been normalized to line feeds. UAs that recognize other newline representations must apply thelastSwhite space processing rules as if this normalization has taken place. If no newline rules are specified for the document language, each carriage return (U+000D) and CRLF sequence (U+000D U+000A) in thegrammardocument text is treated as single line feed character. This default normalization ruleforcombinatoralso applies toS+:combinator:PLUSS*|GREATERS*|S+andremovegenerated content.[…]
- Each tab (U+0009),
carriage return (U+000D),or space (U+0020) character surrounding a linefeed (U+000A) character is removed if 'white-space' is set to 'normal', 'nowrap', or 'pre-line'.
[2010-08-06] The sentence that absolutely positioned elements do not create line breaking opportunities is normative, not informative.
[2010-08-06] The first paragraph is moved
to 9.2.2.1. Also, as is clear from the tokenizer.latter section, the
resulting language“should” is a “must”:
Any text that is directly contained inside a block container element (not inside an inline element)
shouldmust be treated as an anonymous inline element.
[2010-08-24] More consistent use of “inline-level” and “block-level.” Change:
Then, the
block container's inlines are laid out.grammarentire block iseasiertoreadrendered
[2010-08-04] Clarify that the term
“row group” includes header groups and relies less on specific notations of Flex. C.5.87 Section G.1 Grammar [2007-09-27] Changes to remove ambiguity with respect tofooter groups as
well:
Thus, the
Stokentable model consists of tables, captions, rows, row groups (including header groups andavoidnullablenon-terminals.C.5.88SectionG.2Lexicalscanner[2007-09-27]footer groups), columns, column groups, and cells.
[2010-08-24] XML and HTML5, unlike SGML, do
not automatically remove insignificant white space. Change the tokenizer rule @{C}{H}{A}{R}{S}{E}{T} {return CHARSET_SYM;}rules
for generating anonymous table elements to "@charset " {return CHARSET_SYM;} The @charset must be in lowercase and must have asuppress most white space
afterbetween elements, rather than consider it (as definedthe content of an anonymous
table cell.
[2010-08-24] The static position of absolutely positioned elements between table cells or rows was not very useful. Define that the static position of such an element is found not just as if the element had 'position: static', but also had 'display: inline' and zero width and height.
[2010-04-19] The definitioncaption of the macro “O” is wrong.image still
describes the letters O and o can be written with hexadecimal escapes as “ \4f ” and “ \6f ” respectively ( notimage as “ \51 ” and “ \71 ”).it was in the macro should therefore be O o|\\0{0,4}(4f|6f)(\r\n|[ \t\r\n\f])?|\\o C.5.91 Section G.2 Lexical scanner “The two occurrencesprevious version. Change:
Diagram of
"\377"…”:Therea table with a caption above it; the top margin of the caption is collapsed with the top margin of the table.
[2010-10-13] Clarify which of the two boxes
generated by a TITLE attribute to all linkstable element is the principal box:
In both cases, the table
boxgeneratesan anonymous boxa principal block box called the table wrapper box that contains the table box itself andwhichany caption boxes (in document order). The table box isequaltoa block-level box that contains thelemma.C.6Erratasincetable's internal table boxes. TheCandidateRecommendationofApril2009Thesecaption boxes are block-level boxes that retain their own content, padding, margin, and border areas, and are rendered as normalblocksblock boxes inside thetable wrapper box. Whether theerrataforCSSlevel2revision1,CRversionof23April2009.Thesecorrectionshaveanonymousstatusofcaption boxes are placed before or after the table box is decided by the 'caption-side' property, as described below.The
anonymoustable wrapper box is adraft.C.6.1Section 4.2Rulesforhandlingparsingerrors[2009-08-06]Clarified'block' box if the table is block-level, and an 'inline-block' box if the table is inline-level. Thetable wrapper box establishes a block formatting context. The table box (not therulesanonymousanonymoustable wrapper box) is used when doing baseline vertical alignment forignoringinvalidat-keywords:Invalidat-keywords.Useragentsmustignoreaninvalidat-keywordtogetherwitheverythingfollowingit,upto'inline-table'. Theendwidth of thetable wrapper box is theblockthatcontainsanonymousinvalidat-keyword,oruptoborder-edge width of the table box inside it, as described by section 17.5.2. Percentages on 'width' andincluding'height' on thenextsemicolon(;),oruptable are relative toandincludingthetable wrapper box's containing block, not thenextblock({...}),oranonymoustable wrapper box itself.endofanonymousThe
block(})thatcontainscomputed values of properties 'position', 'float', 'margin-*', 'top', 'right', 'bottom', and 'left' on theinvalidat-keyword,whichevercomesfirst.C.6.2Section 13.3.3Allowedpagebreaks[2009-08-06]Pagebreakstable box arealsoallowedwhenthereisagapafterused on thetable wrapper box instead oflastcontentanonymousablock.Addedthefollowingtothefirstlist:3.Betweentable box. Thecontentedgeofablocktable boxanduses theouteredgesinitial values for those properties.
[2010-10-25] The width of its child content (margin edgesthe table caption
contributes to the width of block-level children or line box edges for inline-level children)the table if there'table-layout' is 'auto':
This gives a
(non-zero)gapbetweenthem.C.6.3Section 15.3Fontfamily:the'font-family'property[2009-08-31]Thelistofkeywordsin“(e.g.,'initial','inherit','default','serif','sans-serif','monospace','fantasy',maximum and'cursive')”isn'tanexample,butminimum width for each column.The caption width minimum (CAPMIN) is
infactdetermined by calculating for each caption the minimum caption outer width as thecompleteandnormativelist.C.6.4Section 15.3.1.1serif[2009-08-31]Spellingerrorsinfontnames.MCW of a hypothetical table cell that contains thecorrectnamesare“ExcelsiorCyrillicUpright”caption formatted as "display: block". The greatest of the minimum caption outer widths is CAPMIN.Column and
“ERBukinist.”C.6.5Section 15.7Fontsize:caption widths influence the'font-size'property[2009-08-31]final table width as follows:
- If the
twonotes“Note:implementationexperience'table' or 'inline-table' element's 'width' property hasdemonstrated…”and“Note2.InCSS1,a computed value (W) other than 'auto', theused width is thesuggestedscalingfactor…sayessentiallyproperty's value as used for layoutsamething.Theyarereplacedgreater of W, CAPMIN, and the minimum width required byasinglenote:Note2.InCSS1,all thesuggestedscalingfactorbetweenadjacentindexeswas1.5,whichuserexperienceprovedtocolumns plus cell spacing or borders (MIN). IfWthe used widthis greater than MIN, the extra width should betoolarge.InCSS2,distributed over thesuggestedscalingfactorforacomputerscreenbetweenadjacentindexeswas1.2,whichstillcreatedissuesforcolumns.- If the
smallsizes.Implementationexperience'table' or 'inline-table' element hasdemonstratedthatafixedratiobetweenadjacentabsolute-sizekeywordsisproblematic,andthisspecificationdoesnotrecommendsuchafixedratio.C.6.6Section 17.5.2.1Fixed'width: auto', thetable width used for layout[2009-05-20]UAsmayrenderextracolumnsused width is the greater of the table's containing block width, CAPMIN, and MIN. However, ifthereareunexpectedeither CAPMIN or the maximum width required by the columnsinlaterrowsplus cell spacing or borders (MAX) is less than that ofa'fixed'the containing block, useMAXmax(MAX, CAPMIN).
[2010-07-15] Clarify that case,the widthheight of the columnsa
table row can be influenced by 'vertical-align' and 'height', but the
content box of the table cell is undefined. C.6.7 Section 17.5.3 Table height layout [2009-08-06] Replaced “ Percentage heights on table cells, table rows,not affected.
[…] it is the maximum of the row's specified 'height', the specified 'height' of each cell in the row, and
tablerowgroupscomputeto'auto'the minimum height (MIN) required byCSS 2.1doesnotdefinehowthe cells
and
In CSS 2.1, the height of a cell box is the
maximum of the tableminimum height required by the content. The tablecellscell's 'height' property and the minimum height required by the content (MIN).rowsiscalculatedwhentheircell's 'height' property can influence the heightisspecifiedusingpercentagevalues.CSS 2.1of the row, but it does notdefineincrease themeaningheight of the cell box.A value of 'auto' for 'height'onrowgroups.C.6.8Appendix G.implies that the value MIN will be used for layout.
[2010-08-24] More consistent use of “inline-level.” Change:
The horizontal alignment of
a cell's inline contentinline-level content within a cell box
[2010-08-06] BCP 47 replaces RFC 3066.
[2010-10-05] HTML defines that HTML's block elements represent a Unicode embedding even if they are displayed inline by means of a style sheet. The default style sheet for HTML didn't yet express that. Add:
html, address,
blockquote,
body, dd, div,
dl, dt, fieldset, form,
frame, frameset,
h1, h2, h3, h4,
h5, h6, noframes,
ol, p, ul, center,
dir, hr, menu, pre { display: block; unicode-bidi: embed }
[2010-07-07] Clarification:
The
stacking order forpainting order for the descendants of an element generating a stacking context (see the 'z-index' property) is: […]
[2010-10-25] The grammar. (The ambiguities only affected spaces and were harmless.)appendix is not normative.