The content
CSS property is used with the ::before
and ::after
pseudo-elements to generate content in an element. Objects inserted using the content
property are anonymous replaced elements.
/* Keywords that cannot be combined with other values */ content: normal; content: none; /* <string> value, non-latin characters must be encoded */ /* e.g. \00A0 for */ content: "prefix"; /* <url> value */ content: url("http://www.example.com/test.png"); /* <counter> values */ content: counter(chapter_counter); content: counters(section_counter, "."); /* attr() value linked to the HTML attribute value */ content: attr(value string); /* Language- and position-dependent keywords */ content: open-quote; content: close-quote; content: no-open-quote; content: no-close-quote; /* Except for normal and none, several values */ /* can be used simultaneously */ content: open-quote chapter_counter; /* Global values */ content: inherit; content: initial; content: unset;
Initial value | normal |
---|---|
Applies to | ::before and ::after pseudo-elements |
Inherited | no |
Media | all |
Computed value | On elements, always computes to normal . On ::before and ::after , if normal is specified, computes to none . Otherwise, for URI values, the absolute URI; for attr() values, the resulting string; for other keywords, as specified. |
Animation type | discrete |
Canonical order | the unique non-ambiguous order defined by the formal grammar |
Syntax
Values
none
- The pseudo-element is not generated.
normal
- Computes to
none
for the::before
and::after
pseudo-elements. <string>
- One or more text characters.
<url>
- A URL that designates an external resource (such as an image). If the resource can't be displayed, it is either ignored or a placeholder is shown.
<counter>
- The value of a CSS counter, generally a number. It can be displayed using either the
counter()
orcounters()
function. -
The
counter()
function has two forms: 'counter(name)' or 'counter(name, style)'. The generated text is the value of the innermost counter of the given name in scope at the given pseudo-element. It is formatted in the specified style (decimal
by default).The
counters()
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 in scope at the given pseudo-element, from outermost to innermost, separated by the specified string. The counters are rendered in the indicated style (decimal
by default). attr(x)
- The value of the element's attribute
x
as a string. If there is no attributex
, an empty string is returned. The case-sensitivity of attribute names depends on the document language. open-quote
|close-quote
- These values are replaced by the appropriate string from the
quotes
property. no-open-quote
|no-close-quote
- Introduces no content, but increments (decrements) the level of nesting for quotes.
Formal syntax
normal | none | [ <content-replacement> | <content-list> ] [/ <string> ]?where
<content-replacement> = <image>
<content-list> = [ <string> | contents | <image> | <quote> | <target> | <leader()> ]+where
<image> = <url> | <image()> | <image-set()> | <element()> | <cross-fade()> | <gradient>
<quote> = open-quote | close-quote | no-open-quote | no-close-quote
<target> = <target-counter()> | <target-counters()> | <target-text()>
<leader()> = leader( <leader-type> )where
<image()> = image( [ [ <image> | <string> ]? , <color>? ]! )
<image-set()> = image-set( <image-set-option># )
<element()> = element( <id-selector> )
<cross-fade()> = cross-fade( <cf-mixing-image> , <cf-final-image>? )
<gradient> = <linear-gradient()> | <repeating-linear-gradient()> | <radial-gradient()> | <repeating-radial-gradient()>
<target-counter()> = target-counter( [ <string> | <url> ] , <custom-ident> , <counter-style>? )
<target-counters()> = target-counters( [ <string> | <url> ] , <custom-ident> , <string> , <counter-style>? )
<target-text()> = target-text( [ <string> | <url> ] , [ content | before | after | first-letter ]? )
<leader-type> = dotted | solid | space | <string>where
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
<image-set-option> = [ <image> | <string> ] <resolution>
<cf-mixing-image> = <percentage>? && <image>
<cf-final-image> = <image> | <color>
<linear-gradient()> = linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )
<repeating-linear-gradient()> = repeating-linear-gradient( [ <angle> | to <side-or-corner> ]? , <color-stop-list> )
<radial-gradient()> = radial-gradient( [ <ending-shape> || <size> ]? [ at <position> ]? , <color-stop-list> )
<repeating-radial-gradient()> = repeating-radial-gradient( [ <ending-shape> || <size> ]? [ at <position> ]? , <color-stop-list> )
<counter-style> = <counter-style-name> | symbols()where
<rgb()> = rgb( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<rgba()> = rgba( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<hsl()> = hsl( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )
<hsla()> = hsla( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )
<side-or-corner> = [ left | right ] || [ top | bottom ]
<color-stop-list> = <color-stop>#{2,}
<ending-shape> = circle | ellipse
<size> = closest-side | farthest-side | closest-corner | farthest-corner | <length> | <length-percentage>{2}
<position> = [[ left | center | right | top | bottom | <length-percentage> ] | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] | [ center | [ left | right ] <length-percentage>? ] && [ center | [ top | bottom ] <length-percentage>? ]]
<counter-style-name> = <custom-ident>where
<alpha-value> = <number> | <percentage>
<hue> = <number> | <angle>
<color-stop> = <color> <length-percentage>?
<length-percentage> = <length> | <percentage>
Examples
Headings and quotes
This example inserts quotation marks around quotes, and adds the word "Chapter" before headings.
HTML
<h1>5</h1> <p>According to Sir Tim Berners-Lee, <q cite="http://www.w3.org/People/Berners-Lee/FAQ.html#Internet">I was lucky enough to invent the Web at the time when the Internet already existed - and had for a decade and a half.</q> We must understand that there is nothing fundamentally wrong with building on the contributions of others. </p> <h1>6</h1> <p>According to the Mozilla Manifesto, <q cite="http://www.mozilla.org/en-US/about/manifesto/">Individuals must have the ability to shape the Internet and their own experiences on the Internet.</q> Therefore, we can infer that contributing to the open web can protect our own individual experiences on it. </p>
CSS
q { color: blue; } q::before { content: open-quote; } q::after { content: close-quote; } h1::before { content: "Chapter "; /* The trailing space creates separation between the added content and the rest of the content */ }
Result
Image combined with text
This example inserts an image before the link. If the image is not found, it inserts text instead.
HTML
<a href="http://www.mozilla.org/en-US/">Mozilla Home Page</a>
CSS
a::before { content: url("https://mozorg.cdn.mozilla.net/media/img/favicon.ico") " MOZILLA: "; font: x-small Arial, sans-serif; color: gray; }
Result
Targeting classes
This example inserts additional text after special items in a list.
HTML
<h2>Paperback Best Sellers</h2> <ol> <li>Political Thriller</li> <li class="new-entry">Halloween Stories</li> <li>My Biography</li> <li class="new-entry">Vampire Romance</li> </ol>
CSS
.new-entry::after { content: " New!"; /* The leading space creates separation between the added content and the rest of the content */ color: red; }
Result
Images and element attributes
This example inserts an image before each link, and adds its id
attribute after.
HTML
<ul> <li><a id="moz" href="http://www.mozilla.org/"> Mozilla Home Page</a></li> <li><a id="mdn" href="https://developer.mozilla.org/"> Mozilla Developer Network</a></li> </ul>
CSS
a { text-decoration: none; border-bottom: 3px dotted navy; } a::after { content: " (" attr(id) ")"; } #moz::before { content: url("https://mozorg.cdn.mozilla.net/media/img/favicon.ico") ; } #mdn::before { content: url("https://mdn.mozillademos.org/files/7691/mdn-favicon16.png") ; } li { margin: 1em; }
Result
Specifications
Specification | Status | Comment |
---|---|---|
CSS Generated Content Module Level 3 The definition of 'content' in that specification. |
Working Draft | |
CSS Level 2 (Revision 1) The definition of 'content' in that specification. |
Recommendation | Initial definition |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|---|
Basic support | 1.0 | (Yes) | 1.0 (1.7 or earlier) | 8.0 | 4.0 | 1.0 |
url() support |
1.0 | ? | 1.0 (1.7 or earlier) | 8.0 | 7.0 | 1.0 |
Feature | Android | Edge | Firefox Mobile (Gecko) | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | 1.0 | (Yes) | 1.0 (1.0) | 8.0 | 9.5 | 1.0 |
url() support |
? | ? | ? | ? | ? | ? |