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Copyright © 2011 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
This CSS3 Module describes how to insert and move content around a document, in order to create footnotes, running headers, and other generated content effects.
This is a public copy of the editors' draft. It is provided for discussion only and may change at any moment. Its publication here does not imply endorsement of its contents by W3C. Don't cite this document other than as work in progress.
The (archived) public mailing list www-style@w3.org (see instructions) is preferred for discussion of this specification. When sending e-mail, please put the text “css3-content” in the subject, preferably like this: “[css3-content] …summary of comment…”
This document was produced by the CSS Working Group (part of the Style Activity).
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
quotes
’ property
counter-increment
’ and ‘counter-reset
’ properties
content
’ property
In some cases, authors may want user agents to render content that does not come from the document tree. One familiar example of this is numbered headings; the author does not want to mark the numbers up explicitly, he or she wants the user agent to generate them automatically. Counters and markers are used to achieve these effects.
INSERT EXAMPLE HERE
Similarly, authors may want the user agent to insert the word "Figure" before the caption of a figure, or "Chapter 7" on a line before the seventh chapter title.
figure > caption::before { content: "Figure: "; } chapter:nth-child(7) > title::before { content: "Chapter 7\A"; }
The last example could also be written in a more generic way using counters:
chapter { counter-increment: chapter; } chapter > title::before { content: "Chapter " counter(chapter) "\A"; }
Another common effect is replacing elements with images or other multimedia content. Since not all user agents support all multimedia formats, fallbacks may have to be provided.
/* Replace <logo> elements with the site's logo, using a format * supported by the UA */ logo { content: url(logo.mov), url(logo.mng), url(logo.png), none; } /* Replace <figure> elements with the referenced document, or, * failing that, with either the contents of the alt attribute or the * contents of the element itself if there is no alt attribute */ figure[alt] { content: attr(href, url), attr(alt); } figure:not([alt]) { content: attr(href, url), contents; }
Another effect commonly requested by authors is that of line numbering.
This module introduces the ‘::line-marker
’ pseudo-element that is attached to
the front of every line box, which can be used for this purpose.
pre { counter-reset: line; } pre::line-marker { counter-increment: line; content: counter(line) "."; }
This pseudo-element can also be used to simulate the indentation style found in e-mail communication:
blockquote { margin: 0; padding: 0 0 0 2em; } blockquote > blockquote { margin-left: -1em; } blockquote::line-marker { width: 2em; text-align: left; content: ">"; }
Generated content based on the cite
and
datetime
attributes can create introductions or citations on
the fly as well.
This module introduces several pseudo-elements and allows them to nest in certain predefined ways. In order to explain the relationships between these nested pseudo-elements, three new terms have been coined.
::before
’ is the element to which it
is attached. Note that an element never has a superior parent, and a
pseudo-element always has exactly one. This term is sometimes shortened
to "superior".
At the heart of generated content lies pseudo-elements. Pseudo-elements create abstractions about the document tree beyond those specified by the document language. For instance, document languages do not offer mechanisms to access the first letter or first line of an element's content. CSS pseudo-elements allow style sheet designers to refer to this otherwise inaccessible information. Pseudo-elements also provide style sheet designers a way to assign style to content that does not exist in the source document. Pseudo elements are defined in the [[SELECTORS]] specification.
::before
’ and ‘::after
’ pseudo-elementsThe ‘::before
’ and ‘::after
’ pseudo-elements are used to insert content
immediately before and immediately after the content of an element (or
other pseudo-element). The ‘content
’ propety is used to specify the
content to insert.
For example, the following rule replaces the content of
<abbr>
elements with the contents of the element's
title
attribute:
abbr { content: attr(title); }
The following rule inserts the string "Note: " before the content of every P element whose "class" attribute has the value "note":
P.note:before { content: "Note: " }
The formatting objects (e.g., boxes) generated by an element include generated content. So, for example, changing the above style sheet to:
P.note:before { content: "Note: " } P.note { border: solid green }
...would cause a solid green border to be rendered around the entire paragraph, including the initial string.
The ‘::before
’ and ‘::after
’ pseudo-elements inherit any inheritable
properties from their superior parent.
For a ‘::before
’ or ‘::after
’ pseudo-element to be generated, the
pseudo-element must not have its ‘content
’ property set to ‘inhibit
’ or its
‘display
’ property set to
‘none
’. Note
that for ‘::before
’ and ‘::after
’ pseudo-elements, the initial value of
‘content
’
computes to ‘inhibit
’.
Using a ‘::before
’ pseudo-element in
the context of the anonymous table elements works exactly as if an actual
element had been introduced. For example:
.example::before { content: "D" }
<table> <tr> <td>A</td> <td>B</td> <td>C</td> </tr> <tr class="example"> <td>E</td> <td>F</td> </tr> </table>
An anonymous table cell box is generated around the ‘::before
’ content in this case, resulting in a
3×2 table.
::marker
’
pseudo-elementFor a ‘::marker
’ pseudo-element to be
generated, its superior parent must have a computed ‘display
’ value of ‘list-item
’.
For further details on the rendering model for list markers, see the CSS3 Lists module.
::line-marker
’ pseudo-elementThe ‘::line-marker
’ pseudo-element is
positioned in exactly the same way as the ‘::marker
’ pseudo-element, but appears on every
line, not just the first.
Line boxes are responsible for generating ‘::line-marker
’ pseudo-elements. For each line, one
such marker is created for every block ancestor in the current block
formatting context. [!CSS21] In addition, for the ‘::line-marker
’ pseudo-element to be created, its
‘content
’
property must have a computed value other than ‘none
’ or ‘inhibit
’.
quotes
’ propertyName: | quotes |
---|---|
Value: | foo | bar |
Initial: | text |
Applies To: | all elements |
Inherited: | no |
Percentages: | N/A |
Media: | visual |
Computed value: | specified value |
This property specifies quotation marks for any number of embedded quotations. Values have the following meanings:
open-quote
’ and ‘close-quote
’
values of the ‘content
’ property produce no quotations
marks, as if they were ‘no-open-quote
’ and ‘no-close-quote
’ respectively.
open-quote
’ and ‘close-quote
’
values of the ‘content
’ property are taken from this
list of pairs of quotation marks (opening and closing). The first
(leftmost) pair represents the outermost level of quotation, the second
pair the first level of embedding, etc. The user agent must apply the
appropriate pair of quotation marks according to the level of embedding.
For example, applying the following style sheet:
/* Specify pairs of quotes for two levels in two languages */ :lang(en) > q { quotes: '"' '"' "'" "'" } :lang(no) > q { quotes: "+" ";" "<" ">" } /* Insert quotes before and after Q element content */ q::before { content: open-quote } q::after { content: close-quote }
to the following HTML fragment:
<HTML lang="en"> <HEAD> <TITLE>Quotes</TITLE> </HEAD> <BODY> <P><Q>Quote me!</Q> </BODY> </HTML>
would allow a user agent to produce:
"Quote me!"
while this HTML fragment:
<HTML lang="no"> <HEAD> <TITLE>Quotes</TITLE> </HEAD> <BODY> <P><Q>Trøndere gråter når <Q>Vinsjan på kaia</Q> blir deklamert.</Q> </BODY> </HTML>
would produce:
+Trøndere gråter når <Vinsjan på kaia> blir deklamert.;
Note. While the quotation marks specified by ‘quotes
’ in the
previous examples are conveniently located on computer keyboards, high
quality typesetting would require different ISO 10646 characters. The
following informative table lists some of the ISO 10646 quotation mark
characters:
Codepoint | Description | |
---|---|---|
" | U+0022 | QUOTATION MARK (the ASCII double quotation mark) |
' | U+0027 | APOSTROPHE (the ASCII single quotation mark) |
‹ | U+2039 | SINGLE LEFT-POINTING ANGLE QUOTATION MARK |
› | U+203A | SINGLE RIGHT-POINTING ANGLE QUOTATION MARK |
« | U+00AB | LEFT-POINTING DOUBLE ANGLE QUOTATION MARK |
» | U+00BB | RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK |
‘ | U+2018 | LEFT SINGLE QUOTATION MARK (single high-6) |
’ | U+2019 | RIGHT SINGLE QUOTATION MARK (single high-9) |
“ | U+201C | LEFT DOUBLE QUOTATION MARK (double high-6) |
” | U+201D | RIGHT DOUBLE QUOTATION MARK (double high-9) |
„ | U+201E | DOUBLE LOW-9 QUOTATION MARK (double low-9) |
content
’ propertyQuotation marks are inserted in appropriate places in a document with
the ‘open-quote
’ and ‘close-quote
’
values of the ‘content
’ property. Each occurrence of
‘open-quote
’ or ‘close-quote
’ is
replaced by one of the strings from the value of ‘quotes
’, based on the
depth of nesting.
‘Open-quote
’ refers to the first of a pair
of quotes, ‘close-quote
’ refers to the second. Which
pair of quotes is used depends on the nesting level of quotes: the number
of occurrences of ‘open-quote
’ in all generated text before
the current occurrence, minus the number of occurrences of ‘close-quote
’. If
the depth is 0, the first pair is used, if the depth is 1, the second pair
is used, etc. If the depth is greater than the number of pairs, the last
pair is repeated.
Note that this quoting depth is independent of the nesting of the source document or the formatting structure.
Some typographic styles require open quotation marks to be repeated
before every paragraph of a quote spanning several paragraphs, but only
the last paragraph ends with a closing quotation mark. In CSS, this can be
achieved by inserting "phantom" closing quotes. The keyword ‘no-close-quote
’ decrements the quoting
level, but does not insert a quotation mark.
The following style sheet puts opening quotation marks on every paragraph in a BLOCKQUOTE, and inserts a single closing quote at the end:
BLOCKQUOTE P:before { content: open-quote } BLOCKQUOTE P:after { content: no-close-quote } BLOCKQUOTE P.last:after { content: close-quote }
This relies on the last paragraph being marked with a class "last", since there are no selectors that can match the last child of an element.
For symmetry, there is also a ‘no-open-quote
’ keyword, which inserts
nothing, but increments the quotation depth by one.
Note. If a quotation is in a different language than the surrounding text, it is customary to quote the text with the quote marks of the language of the surrounding text, not the language of the quotation itself.
For example, French inside English:
English inside French:The device of the order of the garter is “Honi soit qui mal y pense.”
Il disait: + Il faut mettre l'action en ‹ fast forward ›.;
A style sheet like the following will set the ‘quotes
’ property so
that ‘open-quote
’ and ‘close-quote
’
will work correctly on all elements. These rules are for documents that
contain only English, French, or both. One rule is needed for every
additional language. Note the use of the child combinator (">") to set
quotes on elements based on the language of the surrounding text:
:lang(fr) > * { quotes: "+" ";" "\2039" "\203A" } :lang(en) > * { quotes: "\201C" "\201D" "\2018" "\2019" }
The quotation marks for English are shown here in a form that most people will be able to type. If you can type them directly, they will look like this:
:lang(fr) > * { quotes: "+" ";" "‹" "›" } :lang(en) > * { quotes: "“" "”" "‘" "’" }
counter-increment
’ and ‘counter-reset
’
propertiesAutomatic numbering in CSS2 is controlled with two properties, ‘counter-increment
’ and ‘counter-reset
’. The counters defined by these properties
are used with the ‘counter()
’ and
‘counters()
’ functions of the the
‘content
’
property.
Name: | counter-increment |
---|---|
Value: | [ <identifier> <integer>? ]+ | none |
Initial: | note |
Applies To: | all elements, ::before, ::after, ::alternate, ::marker, ::line-marker, margin areas, @footnote areas, and @page context |
Inherited: | no |
Percentages: | N/A |
Media: | all |
Computed value: | specified value |
Name: | counter-reset |
---|---|
Value: | [ <identifier> <integer>? ]+ | none |
Initial: | note |
Applies To: | all elements, ::before, ::after, ::alternate, ::marker, ::line-marker, margin areas, @footnote areas, and @page context |
Inherited: | no |
Percentages: | N/A |
Media: | all |
Computed value: | specified value |
The ‘counter-increment
’ property accepts one or
more names of counters (identifiers), each one optionally followed by an
integer. The integer indicates by how much the counter is incremented for
every occurrence of the element. The default increment is 1. Zero and
negative integers are allowed.
The ‘counter-reset
’ property also contains a
list of one or more names of counters, each one optionally followed by an
integer. The integer gives the value that the counter is set to on each
occurrence of the element. The default is 0.
If ‘counter-increment
’ refers to a counter
that is not in the scope (see below) of any ‘counter-reset
’, the counter is assumed to
have been reset to 0 by the root element.
This example shows a way to number chapters and sections with "Chapter 1", "1.1", "1.2", etc.
H1:before { content: "Chapter " counter(chapter) ". "; counter-increment: chapter; /* Add 1 to chapter */ counter-reset: section; /* Set section to 0 */ } H2:before { content: counter(chapter) "." counter(section) " "; counter-increment: section; }
If an element or pseudo-element resets or increments a counter and also
uses it (in its ‘content
’ property), the counter is used
after being reset or incremented.
If an element or pseudo-element both resets and increments a counter, the counter is reset first and then incremented.
The ‘counter-reset
’ property follows the
cascading rules. Thus, due to cascading, the following style sheet:
H1 { counter-reset: section -1 } H1 { counter-reset: imagenum 99 }
will only reset ‘imagenum
’. To
reset both counters, they have to be specified together:
H1 { counter-reset: section -1 imagenum 99 }
Counters are "self-nesting", in the sense that re-using a counter in a child element automatically creates a new instance of the counter. This is important for situations like lists in HTML, where elements can be nested inside themselves to arbitrary depth. It would be impossible to define uniquely named counters for each level.
Thus, the following suffices to number nested list items. The result is
very similar to that of setting ‘display:list-item
’ and ‘list-style: inside
’ on the LI element:
OL { counter-reset: item } LI { display: block } LI:before { content: counter(item) ". "; counter-increment: item }
The self-nesting is based on the principle that every element or
pseudo-element that has a ‘counter-reset
’ for a counter X, creates a
fresh counter X, the scope of which is the element or
pseudo-element, its following siblings, and all the descendants of the
element or pseudo-element and its following siblings.
In the example above, an OL will create a counter, and all children of the OL will refer to that counter.
If we denote by item[n] the nth instance of the "item" counter, and by "(" and ")" the beginning and end of a scope, then the following HTML fragment will use the indicated counters. (We assume the style sheet as given in the example above).
<OL> <!-- (set item[0] to 0 --> <LI>item <!-- increment item[0] (= 1) --> <LI>item <!-- increment item[0] (= 2) --> <OL> <!-- (set item[1] to 0 --> <LI>item <!-- increment item[1] (= 1) --> <LI>item <!-- increment item[1] (= 2) --> <LI>item <!-- increment item[1] (= 3) --> <OL> <!-- (set item[2] to 0 --> <LI>item <!-- increment item[2] (= 1) --> </OL> <!-- ) --> <OL> <!-- (set item[3] to 0 --> <LI> <!-- increment item[3] (= 1) --> </OL> <!-- ) --> <LI>item <!-- increment item[0] (= 3) --> <LI>item <!-- increment item[0] (= 4) --> </OL> <!-- ) --> <OL> <!-- (reset item[4] to 0 --> <LI>item <!-- increment item[4] (= 1) --> <LI>item <!-- increment item[4] (= 2) --> </OL> <!-- ) -->
The ‘counters()
’ function generates a
string composed of the values of all counters with the same name,
separated by a given string.
The following style sheet numbers nested list items as "1", "1.1", "1.1.1", etc.
OL { counter-reset: item } LI { display: block } LI:before { content: counters(item, "."); counter-increment: item }
The above counters() example would be terribly wrong for the above above example since the last list is number 4. The examples need to reset on the :before pseudo-element for it to work right)
By default, counters are formatted with decimal numbers, but all the
styles available for the ‘list-style-type
’ property are also available
for counters. The notation is:
counter(name)
for the default style, or:
counter(name, <'list-style-type'>)
All the styles are allowed, including the glyph types such as ‘disc
’, ‘circle
’, and
‘square
’.
The ‘none
’
value is also allowed, and causes the counter to generate nothing.
H1:before { content: counter(chno, upper-latin) ". " } H2:before { content: counter(section, upper-roman) " - " } BLOCKQUOTE:after { content: " [" counter(bq, hebrew) "]" } DIV.note:before { content: counter(notecntr, disc) " " } P:before { content: counter(p, none) } /* inserts nothing */
display:
none
’An element that is not displayed (‘display
’ set to ‘none
’) cannot increment or reset a
counter.
For example, with the following style sheet, H2s with class "secret" do
not increment ‘count2
’.
H2.secret {counter-increment: count2; display: none}
Elements with ‘visibility
’ set to ‘hidden
’, on the other hand, do
increment counters.
The ‘list-item
’, ‘section-note
’, ‘endnote
’, and ‘footnote
’ counters are not reserved. They are
ordinary counters that happen to be incremented and used by other
properties as well as the counter properties.
The ‘total-pages
’ counter,
however, is reserved. Resetting or increasing this counter has no effect.
See the Paged Media module [CSS3PAGE] for more information on
this counter.
MERGE WITH GCPM
CSS3 introduces ‘named strings
’,
which are the textual equivalent of counters and which have a distinct
namespace from counters. Named strings follow the same nesting rules as
counters. The ‘string-set
’
property accepts values similar to the ‘content
’ property, including the
extraction of the current value of counters.
Named strings are a convenient way to pull metadata out of the document for insertion into headers and footers. In HTML, for example, META elements contained in the document HEAD can set the value of named strings. In conjunction with attribute selectors, this can be a powerful mechanism:
META[author] { string-set: author attr(author); } HEAD > TITLE { string-set: title contents; } @page:left { @top { text-align: left; vertical-align: middle; content: string(title); } } @page:right { @top { text-align: right; vertical-align: middle; content: string(author); } }
This section is missing a property definition.
This section is missing a definition of the string() function.
The following example captures the contents of H1 elements, which represent chapter names in this hypothetical document.
H1 { string-set: chapter contents; }
When an H1 element is encountered, the ‘chapter
’ string is set to the element's
textual contents, and the previous value of ‘chapter
’, if any, is overwritten.
@counter-styles
’This at-rule can be used to change the counter's default counter style. This is typicially used to change, for example, the footnote style:
@counter-styles { footnote: super-decimal; }
The default list style types for counters is ‘decimal
’ except for the ‘footnote
’ counter which defaults to
‘footnotes
’.
page-policy
’ propertyName: | page-policy |
---|---|
Value: | start | first | last |
Initial: | start |
Applies to: | @counter and @string blocks |
Inherited: | N/A |
Percentages: | N/A |
Media: | paged |
Computed value: | specified value |
‘page-policy
’ determines which page-based
occurance of a given element is applied to a counter or string value:
The following example places the chapter name in the header, specifying that it is the value of the string at the end of the page. Example:
@string chapter { page-policy: last; } @page { size: 21.0cm 29.7cm; /* A4 */ @top { text-align: right; vertical-align: center; content: string (chapter); } }
To use the chapter name as it was when the processing of the page
started, the designer would specify a ‘page-policy
’ of ‘start
’ instead of ‘last
’. Designers can also use the value of a
string or counter after its first state change on a page by specifying
‘first
’.
content
’ propertyName: | content |
---|---|
Value: | [ [ <uri> | icon ] ‘, ’ ]* [
normal | none | inhibit | <content-list> ]
|
Initial: | normal |
Applies To: | all elements, ::before, ::after, ::alternate, ::marker, ::line-marker, margin areas, and @footnote areas |
Inherited: | no |
Percentages: | N/A |
Media: | all |
Computed value: | The specified value with each occurrence of ‘normal ’ expanded
as per the prose below.
|
The ‘content
’ property dictates what is
rendered inside the element or pseudo-element. It takes a comma separated
list of URIs followed by a space separated list of tokens. If there are
multiple URIs provided, then each is tried in turn until a value which is
both available and supported is found. The last value is used as a
fallback if the others fail.
For URIs other than URIs in the last comma separated section of the value, as those in the following example:
h1 { content: url(header/mng), url(header/png), none; }
...then if the URI is available and the format is supported, then the
element or pseudo-element becomes a replaced element, otherwise, the
next item in the comma separated list is used, if any. In the example
above, if ‘header/mng
’ wasn't in a
supported format, then ‘header/png
’
would have been used instead. In the example above, if ‘header/png
’ wasn't available either, then the
<h1> element would be empty, as the last alternative is ‘none
’.
To make an element fallback on its contents, you have to explicitly
give ‘contents
’ as a fallback:
content: url(1), url(2), url(3), contents;
If the URI is part of the last comma separated value in the list, as the second URI in the following example:
h1 { content: url(welcome), "Welcome to: " url(logo); }
...then if the file is available and the format is supported, then an anonymous replaced inline element is inserted, otherwise the image is ignored (as if it hadn't been given at all).
When a URI is used as replaced content, it affects the generation of ‘::before
’ and ‘::after
’ pseudo-elements.
<uri>
’ value above, but takes the resource
from the ‘icon
’ property. If the
‘icon
’ property has the value
‘none
’ then
this is equivalent to the case where the given URI is not available.
For an element, this computes to ‘contents
’.
For ‘::alternate
’, if the superior
parent uses the ‘footnote
’,
‘endnote
’, or ‘section-note
’ counter in its ‘content
’ property
then the computed value of ‘content
’ is ‘contents
’,
otherwise it computes to ‘inhibit
’.
For ‘::before
’, ‘::after
’, and ‘::line-marker
’ this computes to ‘inhibit
’.
For ‘::marker
’, if the superior
parent's superior parent uses ‘footnote
’ in its ‘content
’ property
then ‘normal
’ computes to the computed value
of the ‘list-style-image
’
property if the list-style-image is not ‘none
’, otherwise ‘counter(footnote, <list-style-type>)
"suffix"
’ where <list-style-type> is the
computed value of the ‘list-style-type
’ property if that property
is not ‘none
’ and suffix is the
suffix appropriate for that list style type, otherwise ‘inhibit
’.
For ‘::marker
’, if the superior
parent's superior parent uses ‘endnote
’ in its ‘content
’ property
then ‘normal
’ computes to the computed value
of the ‘list-style-image
’
property if the list-style-image is not ‘none
’, otherwise ‘counter(endnote, <list-style-type>)
"suffix"
’ where <list-style-type> is the
computed value of the ‘list-style-type
’ property if that property
is not ‘none
’ and suffix is the
suffix appropriate for that list style type, otherwise ‘inhibit
’.
For ‘::marker
’, if the superior
parent's superior parent uses ‘section-note
’ in its ‘content
’ property
then ‘normal
’ computes to the computed value
of the ‘list-style-image
’
property if the list-style-image is not ‘none
’, otherwise ‘counter(section-note, <list-style-type>)
"suffix"
’ where <list-style-type> is the
computed value of the ‘list-style-type
’ property if that property
is not ‘none
’ and suffix is the
suffix appropriate for that list style type, otherwise ‘inhibit
’.
Otherwise, for ‘::marker
’, if the
computed value of ‘display
’ for
the superior parent is ‘list-item
’ then ‘normal
’ computes to
the computed value of the ‘list-style-image
’ property if the
list-style-image is not ‘none
’, otherwise ‘counter(list-item, <list-style-type>)
"suffix"
’ where <list-style-type> is the
computed value of the ‘list-style-type
’ property if that property
is not ‘none
’ and suffix is the
suffix appropriate for that list style type, otherwise ‘inhibit
’.
For the ‘@footnote
’ area, it
computes to ‘pending(footnote)
’.
For margin areas, it computes to ‘none
’.
On elements, this inhibits the children of the element from being rendered as children of this element, as if the element was empty.
On pseudo-elements it causes the pseudo-element to have no content.
In neither case does it prevent any pseudo-elements which have this element or pseudo-element as a superior from being generated.
On elements, this inhibits the children of the element from being rendered as children of this element, as if the element was empty.
On pseudo-elements, this inhibits the creation of the pseudo-element,
as if ‘display
’ computed to
‘none
’.
In both cases, this further inhibits the creation of any pseudo-elements which have this pseudo-element as a superior.
[ pending(<identifier>) | <string> | contents | footnote | endnote | section-note | list-item | <counters> | <strings> | open-quote | close-quote | no-open-quote | no-close-quote | icon | <glyph> | <uri> | <datetime> | document-url | <target> ]+
One or more of the following values, concatenated.
This causes all elements and pseudo-elements whose ‘move-to
’ property computes to the
specified identifier to be inserted as children of the current element
(or pseudo-element). Note: This doesn't change the DOM, and elements
and pseudo-elements that have been moved inherit from their position
in the DOM, not from their new position.
This must be the case, because otherwise it
would be impossible to determine the value of ‘move-to
’. Unfortunately, this can cause
some unfortunate discontinuities, such as adjacent footnotes using
different fonts because they were moved from elements with different
fonts. It is therefore important that moved content be styled with the
new location in mind.
Note that only elements and pseudo-element that have not yet been reinserted into content are moved. For example:
moved { move-to: insert; } insert { content: pending(insert); } <root> <moved> A </moved> 1 <insert/> 2 <moved> B </moved> 3 <insert/> </root>
...would result in "1 A 2 3 B".
If used on an element or pseudo-element (particularly ‘::alternate
’) which has a ‘move-to
’ property with a computed value
other than ‘here
’, the content
pending at the pseudo-element's superior's position is inserted, not
the content pending at the element or pseudo-element's insertion
point. Similarly if used on a child of an element that has been moved:
the ‘content
’ property is evaluated before
the element is inserted in its new position. This should prevent an
element ever being inserted into itself or other such existential
conundrums.
Counters on content that is moved in this way are evaluated at the point of origin, not the insertion point.
The identifiers ‘here
’ and
‘normal
’
are valid, in that they do not cause a parse error and are not
ignored, but they are useless as the ‘move-to
’ property cannot ever be set to an
identifier with either of those values.
Need to define exactly how this interacts with
‘position:fixed
’. Does ‘position:fixed
’ cause multiple rendering
objects to be created, one per page? If so where does ‘move-to
’ on a ‘position:fixed
’ element move from?
If the element or pseudo-element's ‘display
’ property computes to anything but
‘inline
’ then the element or
pseude-element contains an empty anonymous inline box, otherwise the
element contains an empty string.
(This is a formal way of saying that an empty string is different
from ‘none
’ in that it forces the creation
of a line box, even if the line box would be empty.)
The element or pseudo-element contains the specified string. Occurrences of line-feed or space characters in the string are handled according to the properties given in the Text module.
The element's descendents. Since this can only be used once per element (you can't duplicate the children if, e.g., one is a plugin or form control), it is handled as follows:
Always honoured. Note that this is the default, since the initial
value of ‘content
’ is ‘normal
’ and
‘normal
’ computes to ‘contents
’ on
an element.
::marker
’ or
‘::line-marker
’ pseudo-element:
Evaluates to nothing (like ‘none
’).
Check to see that it is not set on a "previous" pseudo-element, in the following order, depth first:
If it is already used, then it evaluates to nothing (like
‘none
’). Only pseudo-elements that
are actually generated are checked. Thus
/* ::after(2) { content: inhibit; } /* implied by initial value */ ::after(9999) { content: contents }
...would typically not change anything.
So for example, in the following case:
foo { content: none; } foo::before { content: '[' counter(footnote) ']' contents; } foo::alternate { content: counter(footnote) '. ' contents; }
...the ‘::before
’
pseudo-element's contents would become ‘[1]
’, and the footnote would contain
‘1.
’ followed by the element's
contents, because the ‘::alternate
’ takes priority over the
‘::before
’ pseudo-element at the
same depth.
However, in the following case:
/* foo { content: normal; } /* this is the initial value */ foo::after { content: contents; }
...the element's ‘content
’ property would compute to
‘contents
’ and the after pseudo
element would have no contents (equivalent to ‘none
’) and thus
would not appear.
Note that while it is useless to include ‘contents
’
twice in a single ‘content
’ property, that is not a parse
error. The second occurrence simply has no effect, as it has already
been used. It is also not a parse error to use it on a marker
pseudo-element, it is only during the rendering stage that it gets
treated like ‘none
’.
Counters may be specified with two different functions: ‘counter()
’ or ‘counters()
’. The former has two forms:
‘counter(name)
’ or
‘counter(name,
style)
’. The generated text is the value of
the named counter at this point in the formatting structure; it is
formatted in the indicated style (the default is specified using
‘@counter
’ rules). The latter
function also has two forms: 'counters(name,
string)‘ or
’counters(name, string,
style)‘. The generated text is the
value of all counters with the given name at this point in the
formatting structure, separated by the specified string. The counters
are rendered in the indicated style (the default is again specified
using
’@counter' rules). See the section on automatic counters and numbering for more
information.
Set strings may be specified with the ‘string(name)
’ expression. The
generated text is the value of the named string at this point in the
formatting structure. See the section on named
strings for more information.
These values are replaced by the appropriate string from the
‘quotes
’
property.
Inserts nothing (as in ‘none
’), but increments (decrements)
the level of nesting for quotes.
Inserts the specified symbol. The available symbols are:
check
’. (like ✓ U+2713 CHECK
MARK)diamond
’. On some platforms, this is
similar to ‘disc
’. (like ◆ U+25C6 BLACK
DIAMOND or ♦ U+2666 BLACK DIAMOND SUIT)For more information on the list of symbols and their definitions, see the Lists module [CSS3LIST].
Dates and times can be specified with two functions, ‘date()
’ and ‘time()
’. See the section on dates and times for more information.
The URI of the current document. For local files, this may simply be the local file name.
Using the target expressions, authors can write cross-references. Need to write this up.
Sync with GCPM
If the computed value of the part of the ‘content
’ property that ends up being used
is a single URI, then the element or pseudo-element is a replaced element.
The box model defines different rules for the layout of replaced elements
than normal elements. Replaced elements do not have ‘::before
’ and ‘::after
’ pseudo-elements; the ‘content
’ property in
the case of replaced content replaces the entire contents of the element's
box.
Stuart Ballard, David Baron, Bert Bos, and Tantek Çelı̇k provided invaluable suggestions used in this specification.
Property | Values | Initial | Applies to | Inh. | Percentages | Media |
---|---|---|---|---|---|---|
content | [ [ <uri> | icon ] ‘,’ ]* [ normal | none | inhibit | <content-list> ] | normal | all elements, ::before, ::after, ::alternate, ::marker, ::line-marker, margin areas, and @footnote areas | no | N/A | all |
counter-increment | [ <identifier> <integer>? ]+ | none | note | all elements, ::before, ::after, ::alternate, ::marker, ::line-marker, margin areas, @footnote areas, and @page context | no | N/A | all |
counter-reset | [ <identifier> <integer>? ]+ | none | note | all elements, ::before, ::after, ::alternate, ::marker, ::line-marker, margin areas, @footnote areas, and @page context | no | N/A | all |
page-policy | start | first | last | start | @counter and @string blocks | N/A | N/A | paged |
quotes | foo | bar | text | all elements | no | N/A | visual |