content
The content
CSS property replaces an element with a generated value. Objects inserted using the content
property are anonymous replaced elements.
Try it
Syntax
css
/* Keywords that cannot be combined with other values */
content: normal;
content: none;
/* <image> values */
content: url("http://www.example.com/test.png");
content: linear-gradient(#e66465, #9198e5);
content: image-set("image1x.png" 1x, "image2x.png" 2x);
/* alt text for generated content, added in the Level 3 specification */
content: url("http://www.example.com/test.png") / "This is the alt text";
/* <string> value */
content: "prefix";
/* list of content values */
content: "prefix" url("http://www.example.com/test.png");
content: "prefix" url("http://www.example.com/test.png") "suffix" /
"This is some alt text";
/* <counter> values, optionally with <list-style-type> */
content: counter(chapter_counter);
content: counter(chapter_counter, upper-roman);
content: counters(section_counter, ".");
content: counters(section_counter, ".", decimal-leading-zero);
/* 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 counter(chapter_counter);
/* Global values */
content: inherit;
content: initial;
content: revert;
content: revert-layer;
content: unset;
Values
none
-
When applied to a pseudo-element, the pseudo-element is not generated. If applied to an element, the value has no effect.
normal
-
Computes to
none
for the::before
and::after
pseudo-elements. <string>
-
Specifies the "alt text" for the element. This value can be any number of text characters. Non-Latin characters must be encoded using their Unicode escape sequences: for example,
\000A9
represents the copyright symbol. <content-list>
-
A list of anonymous inline boxes that will replace the content of the selected element (in the specified order). This list can include strings, images, counters, and so on.
<image>
-
An
<image>
, denoted by theurl()
orimage-set()
or<gradient>
data type, or part of the webpage, defined by theelement()
function, denoting the content to display. counter()
-
The value of a CSS counter, generally a number produced by computations defined by
<counter-reset>
and<counter-increment>
properties. It can be displayed using either thecounter()
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<list-style-type>
(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<list-style-type>
(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.
<content-list> / "Alternative text"
-
Alternative text may be specified for an image (or list of content items) by appending a forward slash and then the text. The alternative text is intended for speech output by screen-readers, but may also be displayed in some browsers. Note that if the browser does not support alternative text, neither the content or alternative text will be used.
Accessibility concerns
CSS-generated content is not included in the DOM. Because of this, it will not be represented in the accessibility tree and certain assistive technology/browser combinations will not announce it. If the content conveys information that is critical to understanding the page's purpose, it is better to include it in the main document.
Formal definition
Initial value | normal |
---|---|
Applies to | All elements, tree-abiding pseudo-elements, and page margin boxes |
Inherited | no |
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 |
Formal syntax
content =
normal |
none |
[ <content-replacement> | <content-list> ] [ / [ <string> | <counter> ]+ ]? |
element( )
<content-replacement> =
<image>
<content-list> =
[ <string> | contents | <image> | <counter> | <quote> | <target> | <leader()> ]+
<counter> =
<counter()> |
<counters()>
<image> =
<url> |
<gradient>
<quote> =
open-quote |
close-quote |
no-open-quote |
no-close-quote
<target> =
<target-counter()> |
<target-counters()> |
<target-text()>
<leader()> =
leader( <leader-type> )
<counter()> =
counter( <counter-name> , <counter-style>? )
<counters()> =
counters( <counter-name> , <string> , <counter-style>? )
<url> =
url( <string> <url-modifier>* ) |
src( <string> <url-modifier>* )
<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>
<counter-style> =
<counter-style-name> |
<symbols()>
<symbols()> =
symbols( <symbols-type>? [ <string> | <image> ]+ )
<symbols-type> =
cyclic |
numeric |
alphabetic |
symbolic |
fixed
Examples
Headings and quotes
This example inserts quotation marks around quotes, and adds the word "Chapter" before headings.
HTML
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
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 alternative text
This example inserts an image before the link and provides alternative text that a screen reader can output as speech. Some browsers may also display the alternative text.
HTML
html
<a href="https://www.mozilla.org/en-US/">Mozilla Home Page</a>
CSS
The CSS to show the image and set the alternative text is shown below. This also sets the font and color for the content. This will only be used on browsers that display the alternative text.
css
a::before {
content: url("https://mozorg.cdn.mozilla.net/media/img/favicon.ico") /
" MOZILLA: ";
font: x-small Arial, sans-serif;
color: gray;
}
Result
The browser should display the icon before the link below. If using a screen reader, it should speak the word "MOZILLA" when it reaches the image.
Note that on a browser that does not support the alternative text syntax, the whole line is invalid. In this case neither the image or alternative text will be used! You could partially address this issue by including CSS that adds the image before the line with them both.
Targeting classes
This example inserts additional text after special items in a list.
HTML
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
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
html
<ul>
<li><a id="moz" href="https://www.mozilla.org/"> Mozilla Home Page</a></li>
<li>
<a id="mdn" href="https://developer.mozilla.org/">
Mozilla Developer Network</a
>
</li>
</ul>
CSS
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("mdn-favicon16.png");
}
li {
margin: 1em;
}
Result
Element replacement with url()
This example replaces an element's content with an image url()
. Content added with ::before
or ::after
will not be generated as the contents of the element have been replaced.
HTML
html
<div id="replaced">Mozilla</div>
CSS
css
#replaced {
content: url("mdn.svg");
}
/* will not show if element replacement is supported */
#replaced::after {
content: " (" attr(id) ")";
}
Result
Element replacement with <gradient>
This example replaces an element's content with a linear-gradient()
.
HTML
html
<div id="replaced">Mozilla</div>
CSS
css
#replaced {
content: linear-gradient(purple, yellow);
}
Result
Element replacement with image-set()
This example replaces an element's content with a image-set()
. If the users display has normal resolution the 1x.png
will be displayed screens with a higher resolution will display the 2x.png
image.
HTML
html
<div id="replaced">Mozilla</div>
CSS
css
#replaced {
content: image-set(
"1x.png" 1x,
"2x.png" 2x
);
}
Result
Specifications
Specification |
---|
CSS Generated Content Module Level 3 # content-property |
Browser compatibility
BCD tables only load in the browser
See also
- Replaced elements
::after
::before
::marker
contain
quotes
<gradient>
image-set()
functionurl()
function