CSS Pseudo-element
What are Pseudo-Elements?
To style specific portions of an element, utilize a CSS pseudo-element.
It can be utilized, for instance, to:
- Style an element’s initial letter or line
- Add content either before or after an element’s content.
Syntax
The way pseudo-elements are written:
selector::pseudo-element {
property: value;
}
The ::first-line Pseudo-element
A text’s opening line can have a unique style applied to it by using the ::first-line pseudo-element.
The first line of the text in each of the <p> elements is formatted like the example below:
Example
p::first-line {
color: #ff0000;
font-variant: small-caps;
}
Note: It should be noted that only block-level components may use the ::first-line pseudo-element.
The ::first-line pseudo-element has the following characteristics:
- 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-line
In CSS3, the single colon was substituted with a double colon for pseudo-element notation. W3C made an attempt to differentiate between pseudo-elements and pseudo-classes with this approach.
In CSS2 and CSS1, the pseudo-class and pseudo-element syntaxes were both single-colon based.
For CSS2 and CSS1 pseudo-elements, the single-colon syntax is appropriate for backward compatibility.
The ::first-letter Pseudo-element
A text’s initial letter can have a unique style applied to it by using the ::first-letter pseudo-element.
The first letter of the text in each of the <p> elements is formatted in the example below:
Example
p::first-letter {
color: #ff0000;
font-size: xx-large;
}
Note: Only block-level elements are eligible to use the::first-letter pseudo-element.
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
HTML classes can be paired with pseudo-elements:
Example
p.intro::first-letter {
color: #ff0000;
font-size: 200%;
}
The initial letter of paragraphs with class=”intro” will be shown in the example above, larger and in red.
Multiple Pseudo-elements
It’s also possible to mix multiple pseudo-elements.
The first letter of a paragraph in the example below will be red and written in a xx-large font size. The initial line will be all capitalized and blue. The default font size and color will be used for the remainder of the paragraph:
Example
p::first-letter {
color: #ff0000;
font-size: xx-large;
}
p::first-line {
color: #0000ff;
font-variant: small-caps;
}
CSS - The ::before Pseudo-element
You can add content before an element’s content by using the ::before pseudo-element.
An picture is inserted before each <h1> element’s content in the example below:
Example
h1::before {
content: url(smiley.gif);
}
CSS - The ::after Pseudo-element
You can add content after an element’s content by using the ::after pseudo-element.
An picture is inserted after each <h1> element’s content in the example below:
Example
h1::after {
content: url(smiley.gif);
}
CSS - The ::marker Pseudo-element
The markers of list items are chosen via the ::marker pseudo-element.
The list item markers are styled in the example that follows:
Example
::marker {
color: red;
font-size: 23px;
}
CSS - The ::selection Pseudo-element
The ::selection The user-selected piece of an element is matched by a pseudo-element.
::selection can have the following CSS properties applied to it: outline, color, background, and cursor.
The selected text is shown red on a yellow backdrop in the example below:
Example
::selection {
color: red;
background: yellow;
}
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 |
CSS Display/Visibility Properties
| 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 |
