CSS Pseudo-elements

Guest · Post by **Guest** » Fri Oct 27, 2023 8:23 am

CSS Pseudo-elements

What are Pseudo-Elements?
A CSS pseudo-element is used to style specified parts of an element.
For example, it can be used to:

Style the first letter, or line, of an element
Insert content before, or after, the content of an element

Syntax
The syntax of pseudo-elements:

selector::pseudo-element {  property: value;}

The ::first-line Pseudo-element
The ::first-line pseudo-element is used to add a special style
to the first line of a text.
The following example formats the first line of the text in all <p>
elements:

Example

p::first-line
{

color: #ff0000;

font-variant: small-caps;
}
Try it Yourself »

Note: The ::first-line pseudo-element can only be applied to block-level
elements.
The following properties apply to the ::first-line
pseudo-element:

font properties
color properties
background properties
word-spacing
letter-spacing
text-decoration
vertical-align
text-transform
line-height
clear

Notice the double colon notation - ::first-line versus
:first-lineThe double colon replaced the single-colon
notation for pseudo-elements in CSS3. This was an attempt from W3C to
distinguish between pseudo-classes
and pseudo-elements.The single-colon syntax was used
for both pseudo-classes and pseudo-elements in CSS2 and CSS1.For
backward compatibility, the single-colon syntax is acceptable for CSS2 and CSS1
pseudo-elements.

The ::first-letter Pseudo-element
The ::first-letter pseudo-element is used to add a special style to the first
letter of a text.
The following example formats the first letter of the text in all <p>
elements:

Example

p::first-letter
{

color: #ff0000;

font-size: xx-large;
}
Try it Yourself »

Note: The ::first-letter pseudo-element can only be applied to block-level
elements.
The following properties apply to the ::first-letter pseudo- element:

font properties
color properties
background properties
margin properties
padding properties
border properties
text-decoration
vertical-align (only if "float" is "none")
text-transform
line-height
float
clear

Pseudo-elements and HTML Classes
Pseudo-elements can be combined with HTML classes:

Example

p.intro::first-letter {  color: #ff0000;
font-size: 200%;}
Try it Yourself »

The example above will display the first letter of paragraphs with class="intro", in
red and in a larger size.

Multiple Pseudo-elements
Several pseudo-elements can also be combined.
In the following example, the first letter of a paragraph will be red, in
an xx-large font size. The rest of the first line will be blue, and in
small-caps. The rest of the paragraph will be the default font size and color:

Example

p::first-letter
{
  color: #ff0000;
  font-size: xx-large;
}
p::first-line
{

color: #0000ff;

font-variant: small-caps;
}
Try it Yourself »

CSS - The ::before Pseudo-element
The ::before pseudo-element can be used to insert some content before the content of an element.
The following example inserts an image before the content of each <h1> element:

Example

h1::before
{
  content: url(smiley.gif);
}
Try it Yourself »

CSS - The ::after Pseudo-element
The ::after pseudo-element can be used to insert some content after the content of an element.
The following example inserts an image after the content of each <h1> element:

Example

h1::after
{
  content: url(smiley.gif);
}
Try it Yourself »

CSS - The ::marker Pseudo-element
The ::marker pseudo-element selects the
markers of list items.
The following example styles the markers of list items:

Example

::marker {
  color: red; font-size: 23px;
}
Try it Yourself »

CSS - The ::selection Pseudo-element
The ::selection pseudo-element matches the portion of an element that is
selected by a user.
The following CSS properties can be applied to ::selection:
color,
background, cursor, and outline.
The following example makes the selected text red on a yellow background:

Example

::selection {  color: red;
background: yellow;}
Try it Yourself »

Test Yourself With Exercises

Exercise:
Set the background-color to red, of the first line of the paragraph.

<style>
{
background-color: red;
}
</style>

<body>

<p class="intro">
In my younger and more vulnerable years
my father gave me some advice that I've
been turning over in my mind ever since.
'Whenever you feel like criticizing anyone,' he told me,
'just remember that all the people in this world
haven't had the advantages that you've had.'
</p>

</body>

Submit Answer »
Start the Exercise

All CSS Pseudo Elements

Selector
Example
Example description

::after
p::after
Insert something after the content of each <p> element

::before
p::before
Insert something before the content of each <p> element

::first-letter
p::first-letter
Selects the first letter of each <p> element

::first-line
p::first-line
Selects the first line of each <p> element

::marker
::marker
Selects the markers of list items

::selection
p::selection
Selects the portion of an element that is selected by a user

All CSS Pseudo Classes

Selector
Example
Example description

:active
a:active
Selects the active link

:checked
input:checked
Selects every checked <input> element

:disabled
input:disabled
Selects every disabled <input> element

:empty
p:empty
Selects every <p> element that has no children

:enabled
input:enabled
Selects every enabled <input> element

:first-child
p:first-child
Selects every <p> elements that is the first child of its parent

:first-of-type
p:first-of-type
Selects every <p> element that is the first <p> element of its parent

:focus
input:focus
Selects the <input> element that has focus

:hover
a:hover
Selects links on mouse over

:in-range
input:in-range
Selects <input> elements with a value within a specified range

:invalid
input:invalid
Selects all <input> elements with an invalid value

:lang(language)
p:lang(it)
Selects every <p> element with a lang attribute value starting with "it"

:last-child
p:last-child
Selects every <p> elements that is the last child of its parent

:last-of-type
p:last-of-type
Selects every <p> element that is the last <p> element of its parent

:link
a:link
Selects all unvisited links

:not(selector)
:not(p)
Selects every element that is not a <p> element

:nth-child(n)
p:nth-child(2)
Selects every <p> element that is the second child of its parent

:nth-last-child(n)
p:nth-last-child(2)
Selects every <p> element that is the second child of its parent, counting from the last child

:nth-last-of-type(n)
p:nth-last-of-type(2)
Selects every <p> element that is the second <p> element of its parent, counting from the last child

:nth-of-type(n)
p:nth-of-type(2)
Selects every <p> element that is the second <p> element of its parent

:only-of-type
p:only-of-type
Selects every <p> element that is the only <p> element of its parent

:only-child
p:only-child
Selects every <p> element that is the only child of its parent

:optional
input:optional
Selects <input> elements with no "required" attribute

:out-of-range
input:out-of-range
Selects <input> elements with a value outside a specified range

:read-only
input:read-only
Selects <input> elements with a "readonly" attribute specified

:read-write
input:read-write
Selects <input> elements with no "readonly" attribute

:required
input:required
Selects <input> elements with a "required" attribute specified

:root
root
Selects the document's root element

:target
#news:target
Selects the current active #news element (clicked on a URL containing that anchor name)

:valid
input:valid
Selects all <input> elements with a valid value

:visited
a:visited
Selects all visited links

★
+1

Reference: https://www.w3schools.com/css/css_pseudo_elements.asp