CSS supports a variety of selectors to identify elements for styling, each with its own set of rules. While most selection methods are straightforward, pseudo-classes and pseudo-elements provide more flexibility. They let you select elements based on their state or position within a structure, or they select specific portions of content.
These selectors can be tricky to use, and it’s easy to mix up pseudo-classes with pseudo-elements, so how do you differentiate between them?
Understanding CSS Pseudo-Classes
A CSS pseudo-class is like a special keyword you can use with selectors to style elements in different ways. These keywords help you target elements when certain things happen, like when a user hovers their mouse over an element, clicks it, or types something into an input field.
Pseudo-classes make your web page more interactive and responsive by changing how elements look or behave based on user actions. When youuse them with other CSS selectors, they provide precise control over styling and interactivity.
CSS Pseudo-Class Syntax and Usage
The syntax for a CSS pseudo-class consists of a colon (:) followed by the name of a pseudo-class. Here’s the basic syntax:
In this syntax:
CSS categorizes pseudo-classes into several groups based on their functionality and the conditions they target. Here are the main categories along with some examples:
User Interaction
Selects an element when the mouse pointer hovers over it.
Selects an element when a user activates it, typically by clicking.
Selects links that the user has visited.
Structural
:first-child
Selects the first child element of a parent.
:last-child
Selects the last child element of a parent.
:nth-child(n)
Selects elements based on their position within a parent, allowing you to target specific children.
Form-Related
Selects disabled form elements.
Selects checked radio buttons or checkboxes.
UI Element State
Selects invalid form elements.
Selects required fields of form elements.
Selects form elements that are optional fields.
Link-Related
Selects unvisited links.
Language-Based
Selects elements based on the language specified in their “lang” attribute.
you may try a common example byapplying :hover effects to imagesin a gallery. Typical styles include enlarging or fading these images when someone hovers over them.
Exploring CSS Pseudo-Elements
A CSS pseudo-element is like a special keyword you can use with selectors to style specific parts of an element’s content or to insert additional content. These keywords allow you to target and style elements based on their content structure.
Pseudo-elementsenhance your web page’s design and layoutby giving you the ability to style elements in ways that were traditionally only possible with real HTML elements.
CSS Pseudo-Element Syntax and Implementation
Pseudo-elements in CSS have a specific syntax that involves using two colons (::) followed by the name of the pseudo-element. Here is the basic syntax:
Here are some of the pseudo-elements:
Inserts content before the content of the selected element.
Inserts content after the content of the selected element.
::first-letter
Styles the first letter of text within an element.
::selection
Styles the portion of text that a user has selected with their cursor.
Styles the marker box of a list item (e.g., the bullet point or number in a list).
Applies styles to cues in media elements like and . Typically, people use it for subtitles and captions.
The::before and ::after pseudo elementscan be particularly tricky to understand, so practicing them will help you master the rest.
Similarities and Differences
Here are the similarities and differences between CSS pseudo-classes and pseudo-elements:
Pseudo-Classes
Pseudo-Elements
Prefixed with a single colon (:).
Prefixed with two colons (::).
Select and style elements based on their state, position, or user interaction.
Style specific parts of an element’s content or create virtual elements.
Can occur at any point within a complex or compound selector.
Must be the final component of a selector and can only appear once.
Content Insertion
Doesn’t insert content, primarily for styling based on state.
Can insert content or virtual elements before or after the selected element’s content.
Typographic Styling
Not typically used for typographic styling.
Used for text and typographic styling (e.g., ::first-line, ::first-letter).
Targeted Parts
Targets entire elements.
Targets specific parts of an element’s content.
Browser Support
Generally well-supported.
Generally well-supported, but some older browsers may have limited support.
Pseudo-classes and pseudo-elements are important in CSS for creating various styles and interactive features. While they have some similarities, they each have their own unique roles in web design and development.
Pseudo-Classes and Pseudo-Elements in Action
You can practice using CSS pseudo-classes and pseudo-elements in different projects to assess your understanding. Examples of easy projects you can do include profile cards, navigation menus, and list styling, among others. These projects provide hands-on experience to improve your CSS skills while incorporating interactivity and style into your web designs.
