Css before after url

::before / ::after

The ::before and ::after pseudo-elements in CSS allows you to insert content onto a page without it needing to be in the HTML. While the end result is not actually in the DOM, it appears on the page as if it is, and would essentially be like this:

• You want the generated content to come before the element content, positionally.
• The ::after content is also “after” in source-order, so it will position on top of ::before if stacked on top of each other naturally.

Note that the content is still inside the element they are applied to. The naming sort of feels like they might come, ya know, before or after the element, but it’s really before or after the other content inside.

The value for content can be:

• A string: content: «a string»; — special characters need to be specially encoded as a unicode entity. See the glyphs page.
• An image: content: url(/path/to/image.jpg); — The image is inserted at it’s exact dimensions and cannot be resized. Since things like gradients are actually images, a pseudo element can be a gradient.
• Nothing: content: «»; — Useful for clearfixes and inserting images as a background-image (set width and height , and can even resize with background-size ).
• A counter: content: counter(li); — Really useful for styling lists (but we also have ::marker for that).
• A line break: content: «Killing \A Me \A Softly»; — Great for when you really need one.

Note that you can insert HTML entities in the content property, but no dice as far as them rendering or anything like that.

content: "
I will not render as a Heading 1
";

Every browser that supports the double colon ( :: ) CSS3 syntax also supports just the ( : ) syntax, but Internet Explorer (IE) 8 only supports the single-colon, so for now, it’s recommended to just use the single-colon for best browser support.

:: is the newer format intended to distinguish pseudo content from pseudo-selectors. If you don’t need IE 8 support, feel free to use the double-colon.

This browser support data is from Caniuse, which has more detail. A number indicates that browser supports the feature at that version and up.

Desktop

Mobile / Tablet

Tricks that use ::before and after

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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

/* Keywords that cannot be combined with other values */ content: normal; content: none; /* 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"; /* 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"; /* values, optionally with */ 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

When applied to a pseudo-element, the pseudo-element is not generated. If applied to an element, the value has no effect.

Computes to none for the ::before and ::after pseudo-elements.

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.

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.

The value of a CSS counter, generally a number produced by computations defined by and properties. It can be displayed using either the counter() or counters() 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 ( 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 ( decimal by default).

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.

These values are replaced by the appropriate string from the quotes property.

Introduces no content, but increments (decrements) the level of nesting for quotes.

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 |
[ | ] [ / [ | ]+ ]? |
element( )

=

=
[ | contents | | | | | ]+

=
|

=
|

=
open-quote |
close-quote |
no-open-quote |
no-close-quote

=
|
|

=
leader( )

=
counter( , ? )

=
counters( , , ? )

=
url( * ) |
src( * )

=
target-counter( [ | ] , , ? )

=
target-counters( [ | ] , , , ? )

=
target-text( [ | ] , [ content | before | after | first-letter ]? )

=
dotted |
solid |
space |

=
|

=
symbols( ? [ | ]+ )

=
cyclic |
numeric |
alphabetic |
symbolic |
fixed

Examples

Headings and quotes

This example inserts quotation marks around quotes, and adds the word «Chapter» before headings.

HTML

h1>5h1> 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>6h1> 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 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

a href="https://www.mozilla.org/en-US/">Mozilla Home Pagea> 

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.

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

h2>Paperback Best Sellersh2> ol> li>Political Thrillerli> li class="new-entry">Halloween Storiesli> li>My Biographyli> li class="new-entry">Vampire Romanceli> 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="https://www.mozilla.org/"> Mozilla Home Pagea>li> li> a id="mdn" href="https://developer.mozilla.org/"> Mozilla Developer Networka > 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("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

CSS

#replaced  content: url("mdn.svg"); > /* will not show if element replacement is supported */ #replaced::after  content: " (" attr(id) ")"; > 

Result

Element replacement with

This example replaces an element’s content with a linear-gradient() .

HTML

CSS

div  width: 100px; height: 100px; border: 1px solid lightgrey; > 

#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

CSS

div  width: 100px; border: 1px solid lightgrey; > 

#replaced  content: image-set( "1x.png" 1x, "2x.png" 2x ); > 

Result

Specifications

Browser compatibility

BCD tables only load in the browser

See also

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This page was last modified on Jul 17, 2023 by MDN contributors.

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