What are the pseudo-class selectors?

Pseudo-class selectors include:hover, :active, :focus, :visited, :link, :first-child, :last-child, :nth-child(n), :nth-last-child (n), :nth-of-type(n), :nth-last-of-type(n), :not(selector), :empty, :checked, :disabled, etc.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

Pseudo-class selector is a powerful selector in CSS, used to select specific states or conditions of elements. Pseudo-class selectors start with a colon (:) and are used to select different element states, such as mouse hover, visited links, element position, etc. The following are common pseudo-class selectors in CSS:

1. :hover: Select the state when the mouse is hovering over the element. Specific styles can be applied to elements when the mouse pointer hovers over them.

2. :active: Select the state in which the element is activated or pressed. Specific styles can be applied to elements when the user clicks or presses the mouse button.

3. :focus: Select the element currently receiving focus. Specific styles can be applied to elements when they are selected or have focus.

4. :visited: Select the visited link. When a user has visited a link, you can apply specific styles to the link.

5. :link: Select an unvisited link. Corresponds to the :visited pseudo-class, used to select unvisited links.

6. :first-child: Select the first child element of the element. Specific styles can be applied to an element when it is the first child of its parent element.

7. :last-child: Select the last child element of the element. Specific styles can be applied to an element when it is the last child of its parent.

8. :nth-child(n): Select the nth child element of the element. A specific style can be applied to an element when it is the nth child of its parent. Where n can be a specific number, a keyword (such as even, odd) or an expression (such as 2n, 3n 1).

9. :nth-last-child(n): Select the nth child element from the bottom of the element. A specific style can be applied to an element when it is the nth child from the last to its parent.

10. :nth-of-type(n): Select the nth element among elements of the same type. A specific style can be applied to an element when it is the nth element of its type.

11. :nth-last-of-type(n): Select the nth element from the last among elements of the same type. You can apply a specific style to an element when it is the nth element from the last of its type.

12. :not(selector): Select elements that do not match a specific selector. You can use this pseudo-selector to exclude specific elements and select other elements to apply styles to.

13. :empty: Select elements without child elements. Specific styles can be applied to an element when it does not have any child elements.

14. :checked: Select the selected form element. Applies to form elements such as checkboxes, radio buttons, and drop-down lists.

15. :disabled: Select disabled form elements. When a form element is disabled, specific styles can be applied to the element.

The above are common pseudo-class selectors in CSS. They can select and style elements in web pages based on the state or conditions of the elements. By rationally using these pseudo-class selectors, we can achieve rich and diverse effects and improve user experience and page readability.

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