content

This article is in need of a technical review.

Summary

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.

  • 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.
  • Animatable no
  • Canonical order the unique non-ambiguous order defined by the formal grammar

Syntax

Formal syntax: normal | none | [ <string> | <uri> | <counter> | attr() | open-quote | close-quote | no-open-quote | no-close-quote ]+
content: normal                                /* Keywords that cannot be combined with other values */
content: none

content: 'prefix'                              /* <string> value, non-latin characters must be encoded e.g. \00A0 for &nbsp; */
content: url(http://www.example.com/test.html) /* <uri> value */
content: chapter_counter                       /* <counter> values */
content: attr(value string)                    /* attr() value linked to the HTML attribute value */
content: open-quote                            /* Language- and position-dependant keywords */
content: close-quote
content: no-open-quote
content: no-close-quote

content: open-quote chapter_counter            /* Except for normal and none, several values can be used simultaneously */

content: inherit

Values

none
The pseudo-element is not generated.
normal
Computes to none for the :before and :after pseudo-elements.
<string>
Text content.
<uri> url()
The value is a URI that designates an external resource (such as an image). If the resource or image can't be displayed, it is either ignored or some placeholder shows up.
<counter>
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 innermost counter of the given name in scope at this pseudo-element; it is formatted in the indicated style ('decimal' by default). 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 in scope at this pseudo-element, from outermost to innermost separated by the specified string. The counters are rendered in the indicated style ('decimal' by default). See the section on automatic counters and numbering for more information. The name must not be 'none', 'inherit' or 'initial'. Such a name causes the declaration to be ignored.
attr(X)
Returns the value of the element's attribute X as a string. If there is no attribute X, 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.

Examples

Code sample - headings and quotes

HTML Content

<h1>5</h1>
<p> We shall start this with a quote from 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> Here we shall quote 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> And so, we can infer that contributing to the open web, can protect our own individual experiences on it.
</p>

CSS Content

q {
    color: #00008B;
    font-style: italic;
}

q::before   { content: open-quote }
q::after    { content: close-quote }

h1::before  { content: "Chapter "; }

Output

Code sample - content with multiple values adding an icon before a link

HTML Content

<a href="http://www.mozilla.org/en-US/">Home Page</a>

CSS Content

a::before{
    content: url(http://www.mozilla.org/favicon.ico) " MOZILLA: ";
    font:    x-small Arial,freeSans,sans-serif;
    color:   gray;
}

Output

Code sample - adding an icon after text in a custom list

HTML Content

<div>
  <ul class="brightIdea">
    <li>This is my first idea</li>
    <li>and another good idea</li>
  </ul>
</div>

CSS Content

/* first import the icon from a suitable site */
@import url(http://weloveiconfonts.com/api/?family=entypo);

.brightIdea li::after{
    content: '\1f4a1';
    font-family: 'entypo', sans-serif;
}

Output

Code sample - class based example

HTML Content

<h2>Paperback best sellers</h2>
<ol>
    <li>Political thriller</li>
    <li class="newEntry">Halloween Stories</li>
    <li>My Biography</li>    
    <li class="newEntry">Vampire Romance</li>
</ol>

CSS Content

/* use a class rather that an element selector to give more flexibility.
Simple string example, but don't forget add a leading space in the text string
for spacing purposes  */

.newEntry::after {
    content: " New!";
    color: red;
}

Output

HTML Content

<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>
    <li><a id="w3c" href="http://www.w3c.org/">
        World Wide Web Consortium</a></li>
</ul>

CSS Content

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) ;
}

#w3c::before {
    content:url(http://w3c.org/2008/site/images/favicon.ico) ;
}

li {
    margin: 1em;
}

Output

Specifications

Specification Status Comment
CSS Level 2 (Revision 1) Recommendation  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 1.0 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 Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 1.0 1.0 (1.0) 8.0 9.5 1.0

See also

Attachments

File Size Date Attached by
MDN logo 16px
The logo of MDN resized to 16 x 16 for demonstration purposes
648 bytes 2014-04-16 13:45:15 J-Mackerel
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